gleaming rover Oct 22, 2020, 6:07 AM

#

they are, and the fact that you can have widgets in notebooks is very nice too

#

you can have interactive graphs

raven ridge Oct 22, 2020, 6:09 AM

#

In any event, I'm not trying to sell anyone on notebooks right now, since that's a pretty big workflow change for someone who is happy without them. If you ever run the Python repl interactively, though, try IPython. You're likely to find it strictly nicer to work with. Same basic workflow, with lots of minor quality of life improvements, and some neat tricks.

grave gale Oct 22, 2020, 6:10 AM

#

Writing a script/module should be the "final product", notebooks for example used to compare things related to each other in some way

safe hedge Oct 22, 2020, 6:11 AM

#

Tbh I do all my data work in R. ggplot >>>>>> anything in python. but now we are seriously off-topic

grave gale Oct 22, 2020, 6:11 AM

#

I use IPython more than notebooks but yeah, I believe that notebooks have their uses also

smoky turret Oct 22, 2020, 6:12 AM

#

as far as data visualization goes, this guy seems to be the guy to listen to, heres a talk I found very interesting https://www.youtube.com/watch?v=vTingdk_pVM

YouTube

PyCon 2019

Jake VanderPlas - How to Think about Data Visualization - PyCon 2019

"Speaker: Jake VanderPlas

The Python world has a staggering array of data visualization tools, and choosing which to use can seem like a daunting task. But which tool you use is far less important than how you use it. In this talk I’ll walk through some of the important consi...

▶ Play video

#

that talk in particular takes its time to ramp up, but man that payoff

unkempt rock Oct 22, 2020, 9:34 AM

#

Hi guys I need help

#

I have already installed python in my Linux pc -

#

Version 3.6

hazy cloak Oct 22, 2020, 10:46 AM

#

Not the right channel, @unkempt rock . See #❓｜how-to-get-help . Also, last python version is 3.9.

desert peak Oct 22, 2020, 12:35 PM

#

Notebooks are an excellent feature that made data analysis way faster on a project I was working on in the past week

#

Especially pandas

sacred tinsel Oct 22, 2020, 12:40 PM

#

notebooks are a super cool tool for some tasks, but they make it too easy to write bad code

#

too often you across something that only works when the cells are executed in a specific order, or doesnt work at all, because the author had some name still in memory that is no longer being declared (or worse is being redeclared somewhere when executed top to bottom)

#

it's a nightmare to debug

desert peak Oct 22, 2020, 12:54 PM

#

that is true. I wasn't doing anything "big" with it

#

imports, data loading, data transformation, output

unkempt rock Oct 22, 2020, 1:50 PM

#

@hazy cloak I I am learning python3.8

#

so that's why I am trying to get it

boreal umbra Oct 22, 2020, 2:37 PM

#

notebooks are a super cool tool for some tasks, but they make it too easy to write bad code
@sacred tinsel a recurring problem I've had while doing help sessions is that people not familiar with programming will use a notebook and not understand why their code doesn't do what they think it does. And then it's a nightmare to help people debug notebooks if you don't know they're using a notebook.

#

it should work!

sacred tinsel Oct 22, 2020, 2:37 PM

#

yea, I usually urge others to break their notebooks into functions and move them to .py modules

#

it's super convenient to be able to hold big data in memory as you're writing the code, but large notebooks become impossible to maintain

#

it doesn't help that I often think of the code that goes into a notebook as "throwaway" and take shortcuts sometimes

boreal umbra Oct 22, 2020, 2:40 PM

#

I've used a system where I write a regular program and then do python -i

#

and then I can mess with the data

sacred tinsel Oct 22, 2020, 2:40 PM

#

oh yes, although I prefer typing code into the notebook over a terminal

#

that's a neat trick though, I could probably make more use of it

boreal umbra Oct 22, 2020, 2:41 PM

#

the use case was I logged all the data a program I wrote was spitting out, and then used eval to reconstruct all the data into a list, and then did sql-like queries to see what was in it

grave jolt Oct 22, 2020, 2:42 PM

#

you can also use ipdb and just put breakpoint() where you want to run an interactive debugger

raven ridge Oct 22, 2020, 3:46 PM

#

I've used a system where I write a regular program and then do python -i
@boreal umbra for this use case, try ipython -i. Same workflow, but it really is a nicer repl

boreal umbra Oct 22, 2020, 3:46 PM

#

hmm will do @raven ridge

heady mauve Oct 22, 2020, 6:09 PM

#

Is there a way, when writing python code, to ensure that a nop bytecode is placed in the .pyc file when compiled? Or is a breakpoint included in the .pyc file and if so, how do I insert one?

#

Implementation is CPython 3.7.8

grave jolt Oct 22, 2020, 6:16 PM

#

CPython is always compiled to bytecode before running

wicked holly Oct 22, 2020, 6:16 PM

#

are you trying to manipulate the pyc?

grave jolt Oct 22, 2020, 6:16 PM

#

when you do breakpoint(), you're just getting a global variable called breakpoint and calling it

#

But there are ways to not launch the debugger in production.

#

Anyway, this is not the right channel. You can open a help channel in #❓｜how-to-get-help

heady mauve Oct 22, 2020, 7:00 PM

#

ok thanks guys

trail warren Oct 22, 2020, 8:07 PM

#

guys I'd like I've always wanted to learn a bit more about multithreading/multiprocessing, anyone give me some advice on what would be a good way to go about it? The "final" goal is to have good understanding how python/CPython does these things internally, and a bit about how it interacts with the OS to do it.

I could do some sort of general course concerning these topics (I guess that would have to be some sort of general C/C++ course mostly happening at OS level), but it would be cool if I could also play around with stuff using python, and learn by doing.

Then again, I'm not at all experienced at all in python when it comes to lower level stuff, and so it might be best to just start with getting more knowledge concerning that sort of stuff (interpreter/bytecode).

icy tartan Oct 22, 2020, 8:09 PM

#

@trail warren I recommend Raymond Hettinger's talk on concurrency in Python as a good first primer https://www.youtube.com/watch?v=9zinZmE3Ogk

YouTube

SF Python

Raymond Hettinger, Keynote on Concurrency, PyBay 2017

Keynote for https://pybay.com, 2nd annual Regional Python Conference in SF.

Slides: http://pybay.com/site_media/slides/raymond2017-keynote/index.html

▶ Play video

#

It's a nice broad overview of concurrency options available, pros and cons, and a baseline understanding that should help choose where to go from there

trail warren Oct 22, 2020, 8:10 PM

#

looks great, thanks!

boreal umbra Oct 22, 2020, 9:50 PM

#

@trail warren going forward, #async-and-concurrency is the best place to discuss that. That channel isn't limited to just asyncio.

trail warren Oct 22, 2020, 10:16 PM

#

cool, thanks.

magic python Oct 22, 2020, 11:20 PM

#

@sacred tinsel the cell ordering things (re nb's) has a pretty easy fix though - just restart the notebook and run the cells from top to bottom.

worldly venture Oct 22, 2020, 11:33 PM

#

!unshh

fallen slateBOT Oct 22, 2020, 11:33 PM

#

✅ unsilenced current channel.

wild kraken Oct 22, 2020, 11:46 PM

#

"first" 😄

swift imp Oct 22, 2020, 11:48 PM

#

Man people at work treat notebooks like their modules

#

It's terrible

#

Especially with papermill bc they'll submit them to the cluster to run and crap

#

It's like way too much stuff going on in them

gleaming rover Oct 22, 2020, 11:52 PM

#

Man people at work treat notebooks like their modules
@swift imp I think that largely happens with people who aren't software engineers first

#

there was a DS @ my old company who was like that

#

it was pretty demonic

swift imp Oct 22, 2020, 11:56 PM

#

Technically speaking I'm an EE

gleaming rover Oct 22, 2020, 11:57 PM

#

okay, that was not clear

swift imp Oct 22, 2020, 11:57 PM

#

I just have a fetish for doing things lazily which promotes good programming lol

gleaming rover Oct 22, 2020, 11:57 PM

#

I mean, who don't approach problems with the "this is software" mindset

#

...not sure if that makes any more sense

#

like that dude was a statistician first and foremost

#

so he thought of code purely as a way to replace the tools he used to use

swift imp Oct 22, 2020, 11:58 PM

#

Right

#

Makes sense

unkempt rock Oct 23, 2020, 12:36 AM

#

I need a novelty voice TTS engine with python..

#

but the only good engine I see is pyttsx3

#

and microsoft bob is most definitly not a novelty voice...

#

Im specifically trying to approximate glados

#

from portal

#

I found this: https://github.com/EtiennePerot/gladosvoicegen

GitHub

EtiennePerot/gladosvoicegen

GLaDOS voice generator - Windows/Melodyne GUI automation code - EtiennePerot/gladosvoicegen

#

but it looks terrible... and is 6 years old

#

and requires melodyne which wont work on my linux server

#

next I found this

#

https://github.com/kairess/tacotron

GitHub

kairess/tacotron

Portal GLaDOS voice generator. A TensorFlow implementation of Google's Tacotron speech synthesis with pre-trained model (unofficial) - kairess/tacotron

#

but that takes a 130 GB dataset

#

so... yea thats out

gleaming rover Oct 23, 2020, 12:53 AM

#

@unkempt rock this is a language discussion channel. you might want to try #data-science-and-ml or #❓｜how-to-get-help.

unkempt rock Oct 23, 2020, 12:54 AM

#

oh ok

void thorn Oct 23, 2020, 11:54 AM

#

Hey I am getting error while using python audiobook package

FileNotFoundError: [Errno 2] No such file or directory: 'sample.pdf'

amber nexus Oct 23, 2020, 12:04 PM

#

@void thorn Not the channel for that, claim a help channel #❓｜how-to-get-help

scarlet rock Oct 23, 2020, 2:29 PM

#

i have to make a program on steganograhpy as a project

wicked holly Oct 23, 2020, 3:13 PM

#

numpy is good for that

#

are you embedding into images? audio? video? any compression?

runic musk Oct 23, 2020, 4:02 PM

#

is it possible to add a property when creating a class using type()?

flat gazelle Oct 23, 2020, 4:04 PM

#

you can use the property 3 argument constructor

viscid finch Oct 23, 2020, 4:04 PM

#

Is there a way to make a python app or game to .apk plz help

sturdy timber Oct 23, 2020, 4:08 PM

#

Kivy may be what you are looking for https://kivy.org/doc/stable/guide/packaging-android.html

viscid finch Oct 23, 2020, 4:09 PM

#

Ok ty

sturdy timber Oct 23, 2020, 4:09 PM

#

Although this isn't really the channel, sorry didn't realise where we were

#

You should look in #❓｜how-to-get-help in the future

viscid finch Oct 23, 2020, 4:10 PM

#

Ok ty again sir

lavish sparrow Oct 23, 2020, 6:00 PM

#

Hello do you know anyone who does c++ programming?

grave jolt Oct 23, 2020, 6:04 PM

#

@lavish sparrow This is a Python server. If you want help with C++, ask in an off-topic channel or see another server, like https://discord.gg/gn6HH9

west nymph Oct 23, 2020, 6:37 PM

#

The logo for the C & C++ server is a repurposed Rust logo?

#

Is that a subtle dig?

spark magnet Oct 23, 2020, 6:39 PM

#

or just laziness?

wicked holly Oct 23, 2020, 6:39 PM

#

if it is they should just step it up and make it mitchell baker's face

spark magnet Oct 23, 2020, 6:39 PM

#

(or naive misunderstanding about how groups get attached to their imagery)

west nymph Oct 23, 2020, 6:40 PM

#

@spark magnet They modified the Rust logo with a thematically consistent "C & C++".

#

I think that took effort.

wicked holly Oct 23, 2020, 6:41 PM

#

i mean my guess is that the rust cinematic universe has a lot of overlap with C/Cpp

spark magnet Oct 23, 2020, 6:41 PM

#

sure, i meant laziness of imagination

wicked holly Oct 23, 2020, 6:41 PM

#

wouldnt surprise me if the discords were made by the same folks

bleak shard Oct 23, 2020, 8:44 PM

#

c

heady siren Oct 23, 2020, 10:39 PM

#

can i use θ as a variable in python? https://i.imgur.com/ZBf9bo5.png it looks like i can

Imgur

#

any issues that can arise

feral cedar Oct 23, 2020, 10:41 PM

#

people yelling at you

west nymph Oct 23, 2020, 10:41 PM

#

Yes, in Python 3.

grave jolt Oct 23, 2020, 10:41 PM

#

You can if you want, especially if it is some mathematical or physical convention

#

but people will yell at you

radiant fulcrum Oct 23, 2020, 10:44 PM

#

I have a massive amount of respect if you are determined enough to manually set all of the symbols instead of just using their names 🤣

grave jolt Oct 23, 2020, 10:45 PM

#

In Julia you can type \pi in the repl, and it will insert the pi letter, for example. Maybe you can create something like this for your editor.

#

but theta is fine

heady siren Oct 23, 2020, 10:46 PM

#

https://i.imgur.com/tkqov9E.png https://i.imgur.com/dlLyTda.png what looks better

Imgur

grave jolt Oct 23, 2020, 10:46 PM

#

it's weird that it's a container

peak spoke Oct 23, 2020, 10:47 PM

#

The one you can type on a normal keyboard; just stick to basic ascii for var names (or whole source) unless there's some special case or an another language for the devs

gloomy rain Oct 23, 2020, 10:47 PM

#

Feels like it would be a bit of a hassle if you ever wanted to view the code via a terminal without proper encoding configuration.

feral cedar Oct 23, 2020, 10:48 PM

#

wait, what are you storing in theta, if not an angle

heady siren Oct 23, 2020, 10:48 PM

#

📎 unknown.png

feral cedar Oct 23, 2020, 10:49 PM

#

i c

grave jolt Oct 23, 2020, 10:49 PM

#

oh, ok

sick sedge Oct 23, 2020, 11:15 PM

#

anybody good with making .py to .exe? bc i get an error

granite current Oct 23, 2020, 11:18 PM

#

Hey, I saw this discord has a bot that evaluates arbitrary python code, to my knowledge this is insecure and vulnerable to exploits, I imagine this is fixed in some way for the bot. Could anyone tell me how this is done, or point me in the right direction? Thanks!

#

@sick sedge you might want to give https://pypi.org/project/auto-py-to-exe/ a shot

PyPI

auto-py-to-exe

Converts .py to .exe using a simple graphical interface.

grave jolt Oct 23, 2020, 11:19 PM

#

@granite current This is done in a safe sandbox using nsjail: https://github.com/python-discord/snekbox.

heady mauve Oct 23, 2020, 11:19 PM

#

anybody good with making .py to .exe? bc i get an error
@sick sedge try TechWithTim's pyinstaller tutorial on youtube

grave jolt Oct 23, 2020, 11:19 PM

#

@sick sedge This is not a help channel. See #❓｜how-to-get-help to get help.

granite current Oct 23, 2020, 11:20 PM

#

@grave jolt I wasnt aware of this project, thanks!

feral cedar Oct 23, 2020, 11:20 PM

#

yeah, it's definitely not a naked eval

grave jolt Oct 23, 2020, 11:20 PM

#

@granite current The central tool is nsjail. It can be a bit tricky to configure, but it's worth it.

granite current Oct 23, 2020, 11:22 PM

#

Sadly I'd need it to work on windows, still interesting to read up on though

spark magnet Oct 23, 2020, 11:24 PM

#

@granite current these things always rely on the OS to provide the isolation

#

I built one for Ubuntu that used AppArmor

radiant fulcrum Oct 23, 2020, 11:25 PM

#

Could possibly for windows make use of hyper v and a VM to isolate it some what but I'm definately not going to gatentee how secure it is

granite current Oct 23, 2020, 11:26 PM

#

Yeah I'm broadly aware of these tools, mainly for use with docker, but I'm really looking for a good windows solution, with a vm sadly not being an option @spark magnet

#

@radiant fulcrum It'd be for use in a game, so I can't really virtualise

radiant fulcrum Oct 23, 2020, 11:27 PM

#

Hmm probably a bit of a yikes

grave jolt Oct 23, 2020, 11:27 PM

#

You want to run user Python code in a game?

granite current Oct 23, 2020, 11:27 PM

#

yeah it is my best option right now is pypy

radiant fulcrum Oct 23, 2020, 11:27 PM

#

I highly doubt docker is secure enough even if you lock it down fully

#

PyPy isn't anything similar

#

It's a python jit

grave jolt Oct 23, 2020, 11:28 PM

#

it has some kind of sandbox, but idk how good it is

granite current Oct 23, 2020, 11:28 PM

#

no I wouldnt use docker for this i meant ive used apparmor in docker to shore it up for something unrelated

#

@radiant fulcrum pypy still runs python code i dont really care how too much

radiant fulcrum Oct 23, 2020, 11:28 PM

#

I know docker can (on Windows) lock everything down right down to ipc

granite current Oct 23, 2020, 11:28 PM

#

@grave jolt it's not very finished i would have to do a lot of work myself

spark magnet Oct 23, 2020, 11:28 PM

#

@granite current PyPy by itself provides no isolation. it has a sandbox features sort of, but you have to use it.

granite current Oct 23, 2020, 11:29 PM

#

@spark magnet yes I'm aware their current implementation would be too slow anyway

radiant fulcrum Oct 23, 2020, 11:30 PM

#

Does it need to be this secure if this is (I assume) running on your pc as more of a test bench?

spark magnet Oct 23, 2020, 11:30 PM

#

@granite current too slow? PyPy is often faster

granite current Oct 23, 2020, 11:30 PM

#

@spark magnet Sorry, I was referring to how the sandboxing is done, ultimately all code has to be stringified at some point to be passed into the sandbox

radiant fulcrum Oct 23, 2020, 11:31 PM

#

That's the same for pretty much everything

granite current Oct 23, 2020, 11:33 PM

#

@radiant fulcrum could you give me an example

#

Maybe I'm looking at this wrong then

radiant fulcrum Oct 23, 2020, 11:33 PM

#

Example of what

granite current Oct 23, 2020, 11:34 PM

#

@radiant fulcrum I assumed you replied to me saying that code would have to be stringified to be sandboxed? if so could you give me an example of that outside of pypy sandboxing?

radiant fulcrum Oct 23, 2020, 11:36 PM

#

Any code that you would send to a sandbox would end up being stringified because they're ultimately ran in a seperate process that's isolated and that process needs to have the code to be executed

#

If you're aim is to have it essentially execute the code in isolation in the same process I don't think that's possible regardless of the system without isolating the entire process to begin with

granite current Oct 23, 2020, 11:38 PM

#

@radiant fulcrum Yeah you are correct on that that is my aim, usually lua is used for this purpose because its relatively easy to implement this

radiant fulcrum Oct 23, 2020, 11:38 PM

#

Alot easier todo with a language designed to be sandboxed

granite current Oct 23, 2020, 11:39 PM

#

exactly

radiant fulcrum Oct 23, 2020, 11:39 PM

#

Python was never really made with sandboxing in mind so you will 3nd up spawning seperate processes todo zo

granite current Oct 23, 2020, 11:40 PM

#

You are probably right, that's my impression too, I just saw the bot and I was curious if it maybe used something clever that could be of use to me, sadly thats not the case

#

thanks everyone anyway!

wicked holly Oct 24, 2020, 12:04 AM

#

docker/k8s is negative security benefit, the benefits there are all from a convenience/deployment speed standpoint.

smoky turret Oct 24, 2020, 1:36 AM

#

another little puzzle: Explain why the first two work and the last doesnt

📎 unknown.png

grave jolt Oct 24, 2020, 1:37 AM

#

!warn @unkempt rock Advertisement is not allowed on this server. Keep the channels on topic.

fallen slateBOT Oct 24, 2020, 1:37 AM

#

:incoming_envelope: :ok_hand: applied warning to @unkempt rock.

grave jolt Oct 24, 2020, 1:37 AM

#

@smoky turret (a) is the same as a, not (a,) 😛

smoky turret Oct 24, 2020, 1:38 AM

#

a much faster response than my last puzzle

grave jolt Oct 24, 2020, 1:38 AM

#

!e

print([[[[[42]]]]])
print((((((42))))))

fallen slateBOT Oct 24, 2020, 1:38 AM

#

@grave jolt :white_check_mark: Your eval job has completed with return code 0.

001 | [[[[[42]]]]]
002 | 42

smoky turret Oct 24, 2020, 1:39 AM

#

though my last one was much more interesting

grave jolt Oct 24, 2020, 1:39 AM

#

!e

(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((
(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((
(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((
(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((
42
)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

fallen slateBOT Oct 24, 2020, 1:39 AM

#

@grave jolt :x: Your eval job has completed with return code 1.

001 | s_push: parser stack overflow
002 | MemoryError

smoky turret Oct 24, 2020, 1:39 AM

#

how fun

grave jolt Oct 24, 2020, 1:39 AM

#

interesting that CPython crashes on that and PyPy doesn't

smoky turret Oct 24, 2020, 1:41 AM

#

did you get to see my last puzzle?

#

📎 unknown.png

smoky shuttle Oct 24, 2020, 1:47 AM

#

true

smoky turret Oct 24, 2020, 1:48 AM

#

the question is why is it true

spark magnet Oct 24, 2020, 1:51 AM

#

False == 0 and 0 in [False]

smoky turret Oct 24, 2020, 1:51 AM

#

correct

#

also, hey @spark magnet, I lurk your blog

spark magnet Oct 24, 2020, 1:51 AM

#

nice 🙂

feral cedar Oct 24, 2020, 2:02 AM

#

ooh those are from the wtfpython repo right?

glossy burrow Oct 24, 2020, 2:52 AM

#

?

radiant garden Oct 24, 2020, 3:21 AM

#

https://github.com/satwikkansal/wtfpython

GitHub

satwikkansal/wtfpython

What the f*ck Python? Contribute to satwikkansal/wtfpython development by creating an account on GitHub.

smoky turret Oct 24, 2020, 3:43 AM

#

oh, cool project. I got them from twitter, perhaps they originated from there

bleak lantern Oct 24, 2020, 2:21 PM

#

I'm processing a bunch of data, and wanted to group my data based off "zones". for example, if our "margin = 0.3" i would put it into the zone 0-1, if 'margin=1.5', put it into zone 1-2. I'd like to have some hash table, so that when i say zone['0-1'], it will give me all the IDS of the objects that i appended to that zone.... anyone have any ideas how to do this without doing a bunch of if/else statements?

#

ideally would just like to collections.Counter() all my results

crystal pebble Oct 24, 2020, 2:24 PM

#

Can you write a conversion from margin to zone?

bleak lantern Oct 24, 2020, 2:25 PM

#

@crystal pebble not really sure what u mean by that

#

kind of wanted:
dict['0-1'] = ['over', 'under', 'under']

but the key inputted will be based off the margin's value

#

so if the margin=0.3, it would go into dict['0-1'] key

#

I could do this with a bunch of if/else statements, but when u have 20-30 different keys it will get messy

crystal pebble Oct 24, 2020, 2:28 PM

#

Well, ignoring that for a second... a simple but maybe not great way to do it is to set up an object of some sort. Something like,
[('0-1', range(0, 0.3)), ('1-2', range(0.3, 1))] and then search through it until you find a hit

#

Your predicate would be that whatever number you want is in the range

#

What I was talking about before was converting things. Think F to C or vice versa

#

Hmm... how big are your decimals? You can just multiply them by some large number to get rid of them

#

(I have no idea what does and doesn't work in your case, just throwing out ideas)

#

q = [('A', lambda n: 0 <= n < 0.3), ('B', lambda n: 0.3 <= n < 1)]
list(filter(lambda m: m[1](0.4), q))[0][0]
>>> 'B'```

#

~~It's not clean though~~

#

NP. Good luck

boreal umbra Oct 24, 2020, 2:58 PM

#

@bleak lantern be sure to stick to the channel description in this channel especially. This isn't a help channel.

crystal pebble Oct 24, 2020, 3:04 PM

#

Oops, sorry. I lost track of what room I was in

boreal umbra Oct 24, 2020, 3:05 PM

#

def do_list_stuff():
    list_thing: List[Tuple[str, int, float]]
    list_thing = <some list comp>

#

is this sort of syntax supported by any/all linters?

crystal pebble Oct 24, 2020, 3:05 PM

#

Yes. I'll take a pic, one sec

boreal umbra Oct 24, 2020, 3:06 PM

#

the first line that mentions list_thing doesn't actually assign anything to it but I've had a few cases where I've wanted to specify the type in advance

#

though I wouldn't want that to be the default pattern for using types because then we're tricking people into thinking that you have to declare variables.

crystal pebble Oct 24, 2020, 3:07 PM

#

📎 unknown.png

#

It does warn about list_thing being unused

boreal umbra Oct 24, 2020, 3:08 PM

#

the white block on line 5. Is that a type warning?

crystal pebble Oct 24, 2020, 3:09 PM

#

📎 unknown.png

#

That's the warning for line 5

#

(Hard to take a good screenshot since my name shows up and I don't have paint or anything installed)

boreal umbra Oct 24, 2020, 3:10 PM

#

it looks like it's not really supported by this particular linter, then

crystal pebble Oct 24, 2020, 3:10 PM

#

It may be my configuration. I get the following when I don't have the function there

fallen slateBOT Oct 24, 2020, 3:11 PM

#

You are not allowed to use that command here. Please use the #bot-commands channel instead.

crystal pebble Oct 24, 2020, 3:11 PM

#

📎 unknown.png

boreal umbra Oct 24, 2020, 3:11 PM

#

@kind karma this is a discussion channel. You're welcome to join the conversation but please don't interrupt.

crystal pebble Oct 24, 2020, 3:12 PM

#

📎 unknown.png

boreal umbra Oct 24, 2020, 3:14 PM

#

oh cool @crystal pebble

#

what IDE is this btw?

feral cedar Oct 24, 2020, 3:14 PM

#

neovim?

crystal pebble Oct 24, 2020, 3:14 PM

#

Yeah, with Ale, Pyflakes, and maybe one more thing

feral cedar Oct 24, 2020, 3:14 PM

#

looks pretty good

crystal pebble Oct 24, 2020, 3:14 PM

#

I'm pretty certain you can get it to type check like you want in functions as well, I just don't have it set up properly

boreal umbra Oct 24, 2020, 3:17 PM

#

I also had a case recently where I was using type annotations for a class I was defining

#

let me see

#

class MeasuresDict(UserDict, t.Mapping[str, Measures]):
    ...

crystal pebble Oct 24, 2020, 3:18 PM

#

That definitely works

boreal umbra Oct 24, 2020, 3:18 PM

#

I feel like it should have -> notation

crystal pebble Oct 24, 2020, 3:18 PM

#

That's for the return type only, IIRC

boreal umbra Oct 24, 2020, 3:19 PM

#

yeah, but class is not def, so I don't think it should be required that -> means exactly the same thing

#

I don't know what t.Mapping[str, Measures].__init_subclass__ does but I feel like we're not making a subclass of that in any meaningful way

#

but maybe we are

peak spoke Oct 24, 2020, 3:21 PM

#

The typehint does get put into local __annotations__ si I don't see why an up to date linter wouldn't understand it

boreal umbra Oct 24, 2020, 3:23 PM

#

@peak spoke are you talking about when the type hint is in the class constructor (or whatever ClassName(...) is called), or if the proposed ClassName(...) -> TypeHint[...] were it?

peak spoke Oct 24, 2020, 3:25 PM

#

Was a bit scrolled up, for the previous convo with the typehinted name before it was assigned a value

boreal umbra Oct 24, 2020, 3:25 PM

#

ah yes

true ridge Oct 24, 2020, 3:28 PM

#

The typehint does get put into local __annotations__ si I don't see why an up to date linter wouldn't understand it
@peak spoke No linters knows anything about the __annotations__. It is a runtime attribute inserted by the interpreter, linters does static analysis so they either have to support the PEP 484/526 etc. or just ignore them.

#

is this sort of syntax supported by any/all linters?
@boreal umbra all type checkers whom implement PEP 526 (https://www.python.org/dev/peps/pep-0526/#id7) supports this (which I believe all of them)

Python.org

PEP 526 -- Syntax for Variable Annotations

The official home of the Python Programming Language

#

The general purpose linters usually just ignores the type hints (like pycodestyle / pyflakes)

peak spoke Oct 24, 2020, 3:31 PM

#

They don't know about the attribute, but when it's a thing that's properly constructed and may be used around python with the pep being accepted then I don't see why they'd ignore the hint

true ridge Oct 24, 2020, 3:32 PM

#

The ignoring is done for keeping tools boundaries in a single scope.

#

For example, these guys are the dynamic typing tools (not linters / type checkers) that uses the powers of the __annotations__ https://github.com/ethanhs/python-typecheckers#dynamicruntime

GitHub

ethanhs/python-typecheckers

A list of Python type checkers (PEP 484 compliant and not, static and runtime/dynamic) - ethanhs/python-typecheckers

pliant tusk Oct 24, 2020, 8:53 PM

#

Does anyone know the reason why these are different types?```py

dict.setitem
<slot wrapper 'setitem' of 'dict' objects>
dict.getitem
<method 'getitem' of 'dict' objects>

boreal umbra Oct 24, 2020, 9:15 PM

#

@pliant tusk huh that's a good question

undone flame Oct 24, 2020, 9:15 PM

#

No, that's really interesting. I'd bet that it has to do with c implimentation efficiency, but I have no idea what.

pliant tusk Oct 24, 2020, 9:15 PM

#

im looking at the c implementation, and the getitem method is put in the slot as well

boreal umbra Oct 24, 2020, 9:16 PM

#

I thought slots were to decrease the memory footprint of objects with a fixed number of attributes. But dict items are not attributes

spice pecan Oct 24, 2020, 9:18 PM

#

those are different slots IIRC

pliant tusk Oct 24, 2020, 9:18 PM

#

mp_subscript is set to the same func

undone flame Oct 24, 2020, 9:19 PM

#

Right, and classes have their attributes stored in a dict named .__dict__ unless there's something stored in .__slots__.

spice pecan Oct 24, 2020, 9:19 PM

#

Lists have the same thing, __getitem__ is a method while __setitem__ is a slot-wrapper think

smoky turret Oct 24, 2020, 9:19 PM

#

what im gathering is that slot-wrappers are a thin wrapper over the C Api, but this doesnt explain why set is a slot wrapper and get isnt

📎 unknown.png

undone flame Oct 24, 2020, 9:23 PM

#

But if it works well enough without taking that last __get__() step, maybe nobody bothers...

#

Though that doesn't explain why they're different.

pliant tusk Oct 24, 2020, 9:24 PM

#

>>> type(dict.__getitem__)
<class 'method_descriptor'>``` its actually a method descriptor

#

not wrapper

undone flame Oct 24, 2020, 9:24 PM

#

Oh, good point.

#

dict.__setattr__ and dict.__getattribute are both slot wrappers.

smoky turret Oct 24, 2020, 9:26 PM

#

I want a nice chart of all these odd internal-use types

#

that would be cool

undone flame Oct 24, 2020, 9:52 PM

#

from collections import defaultdict

def attrs(cls):
    ret = {}
    for n in dir(cls):
        v = getattr(cls,n)
        if callable(v):
            vn = repr(v)
            try:
                vn = vn[1:vn.index("'")]
            except:
                vn = vn[1:vn.index(" at ")]
            ret[n]=vn
    return ret

glossary = defaultdict(lambda : defaultdict(set))
classes = {dict, list, int, float, tuple, object, Exception, bool}
for cls in classes:
    w = attrs(cls)
    for k,v in w.items():
        glossary[k][v].add(cls)

pglossary = {k:{kk:vv for kk,vv in v.items()} for k,v in glossary.items()}

difglossary = {k:v for k,v in pglossary.items() if len(v)>1}

pprint(difglossary)```

#

according to ^, only these classes have differences in wrapper types: {'__contains__': {'method ': {<class 'dict'>}, 'slot wrapper ': {<class 'list'>, <class 'tuple'>}}, '__getitem__': {'method ': {<class 'list'>, <class 'dict'>}, 'slot wrapper ': {<class 'tuple'>}}}

#

That's in python 3.8. remind me of other classes you want me to add.

smoky turret Oct 24, 2020, 9:55 PM

#

could add sets

#

array.array

#

bytes

#

str

undone flame Oct 24, 2020, 10:03 PM

#

still only those two attributes.

#

just noticed how weird copyright is. <class '_sitebuiltins._Printer'>

fluid gale Oct 24, 2020, 10:05 PM

#

Thoughts on making a chat bot that learns from the help channels?

undone flame Oct 24, 2020, 10:07 PM

#

Sounds cool.

fluid gale Oct 24, 2020, 10:09 PM

#

Nevermind, I just looked at some of them, not very quality content >.<

cloud crypt Oct 24, 2020, 10:15 PM

#

Is there any way to use 32-bit pointers in 64-bit python with ctypes?

raven ridge Oct 24, 2020, 10:16 PM

#

that question doesn't even really make sense...

cloud crypt Oct 24, 2020, 10:17 PM

#

well yeah but it's hard to explain

raven ridge Oct 24, 2020, 10:17 PM

#

a 64-bit program has a 64-bit address space. So, the location of an individual byte of memory in that address space could be any one of 2**64 different places, and so you need a 64-bit type to represent it.

cloud crypt Oct 24, 2020, 10:18 PM

#

that’s not really my use-case

#

basically I am interacting with a 32-bit process, and having data types in there requires me to use appropriate types

#

think I can just stick integer type instead of a pointer and use it as address, honestly

#

if there isn’t a better solution

raven ridge Oct 24, 2020, 10:20 PM

#

there's not really a difference between a 64-bit pointer type and a 64-bit unsigned integer, in terms of how they're represented in memory. They're different for the type system, but not in terms of binary representation.

cloud crypt Oct 24, 2020, 10:20 PM

#

definitely

#

was wondering if I could use that nice ctypes.POINTER(Type), though

#

but seems like not the case

raven ridge Oct 24, 2020, 10:22 PM

#

ctypes is for code that you're interacting directly with, in DLL's / shared libraries. since a 64-bit process can't load a 32-bit library, there's no reason it would need to have a type representing 32-bit pointers

cloud crypt Oct 24, 2020, 10:23 PM

#

not only shared libraries but yeah

raven ridge Oct 24, 2020, 10:24 PM

#

well, shared libraries or the interpreter itself - that's it, right?

#

I guess it does give you C compatible data types that you could use for structure packing/decoding, too.

cloud crypt Oct 24, 2020, 10:31 PM

#

Yeah, it does

heady siren Oct 25, 2020, 12:47 AM

#

Anyone know the speed difference between cupy and py cuda?

#

It’s not exactly the same type of thing

unkempt rock Oct 25, 2020, 5:41 AM

#

print("Hi I'm Botty the robot. Please enter the the five scores that you")
print("need me to find the average of")

score1=int(input("Enter score 1"))
score2=int(input("Enter score 2"))
score3=int(input("Enter score 3"))
score4=int(input("Enter score 4"))
score5=int(input("Enter score 5"))

#change the total score calculation to include score3, score4, score5
totalscore=score1+score2+score3+score4+score5

#change the formula for average to find the average of 5 values
average= totalscore/2

print(average)

#

Does this work

grave jolt Oct 25, 2020, 5:42 AM

#

@unkempt rock This is a discussion channel, not a help channel. See #❓｜how-to-get-help.

gleaming rover Oct 25, 2020, 6:01 AM

#

do you consider Python lacking block scope desirable?

sacred yew Oct 25, 2020, 6:05 AM

#

tbh there's not really much of a need for block scoping

#

most of the time, when I'm using other languages, I feel that block scoping makes me do more work with no benefit

gleaming rover Oct 25, 2020, 6:06 AM

#

most of the time, when I'm using other languages, I feel that block scoping makes me do more work with no benefit
@sacred yew me too, especially when I want to set multiple variables based on the outcome of a conditional

sacred yew Oct 25, 2020, 6:07 AM

#

yeah that was the main case i was referring to

grave jolt Oct 25, 2020, 6:07 AM

#

There's at least one issue caused by lack of block scoping

e = 1
try:
    1/0
except ZeroDivisionError as e:
    print("it's fine")
print(e) # e is not defined

and it may add more headache with pattern matching

but otherwise, not a big deal for me

gleaming rover Oct 25, 2020, 6:08 AM

#

There's at least one issue caused by lack of block scoping
e = 1
try:
    1/0
except ZeroDivisionError as e:
    print("it's fine")
print(e) # e is not defined
and it may add more headache with pattern matching

but otherwise, not a big deal for me
@grave jolt WTF?

#

why is it like that

grave jolt Oct 25, 2020, 6:08 AM

#

i have no idea

sacred yew Oct 25, 2020, 6:08 AM

#

except deletes the variable at the end of the scope

#

for some reason

grave jolt Oct 25, 2020, 6:09 AM

#

yep

gleaming rover Oct 25, 2020, 6:09 AM

#

no, I mean

#

why?

#

like I get what's happening but is that a deliberate design choice

grave jolt Oct 25, 2020, 6:09 AM

#

we can ask core devs 😄

sacred yew Oct 25, 2020, 6:09 AM

#

i mean, there aren't any more references to e anymore after the except

#

since it was rebound to the exception

gleaming rover Oct 25, 2020, 6:09 AM

#

hm, actually, let me think

#

I suppose it's similar to with-as

#

but the thing is

sacred yew Oct 25, 2020, 6:10 AM

#

the original e value would have been gc'd already, right?

grave jolt Oct 25, 2020, 6:10 AM

#

hm, yes

gleaming rover Oct 25, 2020, 6:10 AM

#

it doesn't make sense to refer to the as binding with with, since presumably it won't be in a usable state after __exit__

#

but that's not the case for except

grave jolt Oct 25, 2020, 6:11 AM

#

with's binding is accessible after the with

sacred yew Oct 25, 2020, 6:11 AM

#

https://stackoverflow.com/questions/24271752/except-clause-deletes-local-variable

Stack Overflow

except-clause deletes local variable

exc = None
try:
raise Exception
except Exception as exc:
pass

...

print(exc)
NameError: name 'exc' is not defined
This used to work in Python2. Why was it changed this way? If I cou...

#

looks like its due to avoiding circular refs

gleaming rover Oct 25, 2020, 6:12 AM

#

with's binding is accessible after the with
@grave jolt wait, it really is

#

🥴

grave jolt Oct 25, 2020, 6:14 AM

#

Another issue is the closure gotcha, but I don't know whether scoped bindings can fix it

fs = []
for x in range(5):
    fs.append(lambda: x)
print(fs[0]())  # 5

fs = []
for (const x of [0, 1, 2, 3, 4]) // x only exists in the scope of the for
    fs.push(() => x);
console.log(fs[0]())  // 0

gleaming rover Oct 25, 2020, 6:15 AM

#

isn't that because of late binding

grave jolt Oct 25, 2020, 6:15 AM

#

Well, the lambda stores a reference to the x in the enclosing scope.

#

And the for loop just performs many assignments

sacred yew Oct 25, 2020, 6:16 AM

#

since it can't store a ref to the current iterations value because of no block scope

grave jolt Oct 25, 2020, 6:16 AM

#

But if it's a new scope every time, it's going to be a different reference every time

#

Basically, lambda doesn't store a reference (pointer) to the object, it stores a reference to a reference to an object.

#

Like, it stores a reference to the local name x

raven ridge Oct 25, 2020, 6:21 AM

#

it doesn't make sense to refer to the as binding with with, since presumably it won't be in a usable state after __exit__
@gleaming rover that's entirely dependent upon the class - in fact, it's pretty common for __enter__ to return self, in which case it's often perfectly valid after __exit__ has run.

grave jolt Oct 25, 2020, 6:22 AM

#

!e

def f():
    def g():
        return x
    def h():
        return x
    x = 5
    return (g, h)

(g, h) = f()

g.__closure__[0].cell_contents = 6
print(g())
print(h())

fallen slateBOT Oct 25, 2020, 6:22 AM

#

@grave jolt :white_check_mark: Your eval job has completed with return code 0.

001 | 6
002 | 6

gleaming rover Oct 25, 2020, 6:22 AM

#

yes, but I have personally never seen context managers being used after their blocks end

#

Like, it stores a reference to the local name x
@grave jolt yeah, but is this behaviour bad?

#

personally I think it's fine...?

grave jolt Oct 25, 2020, 6:23 AM

#

It's bad because of this:

fs = []
for x in range(5):
    fs.append(lambda: x)
print(fs[0]())  # 5
print(fs[1]())  # 5
print(fs[2]())  # 5
print(fs[3]())  # 5
print(fs[4]())  # 5

raven ridge Oct 25, 2020, 6:23 AM

#

yes, but I have personally never seen context managers being used after their blocks end
@gleaming rover it's usually unnecessary, because in the cases where the as variable is still meaningfully usable after the block ends are also the cases where __begin__ doesn't construct a new object, so you'd already have an instance to work with.

grave jolt Oct 25, 2020, 6:24 AM

#

So you have to do fs.append(lambda x=x: x).

raven ridge Oct 25, 2020, 6:24 AM

#

It's a common gotcha.

#

but, to be fair, default parameters being bound at function definition time is an even more common gotcha.

gleaming rover Oct 25, 2020, 6:25 AM

#

It's bad because of this:

fs = []
for x in range(5):
    fs.append(lambda: x)
print(fs[0]())  # 5
print(fs[1]())  # 5
print(fs[2]())  # 5
print(fs[3]())  # 5
print(fs[4]())  # 5

@grave jolt like I get that that's the behaviour

#

but I've made use of it before

#

it (late binding of closures) seems more intuitive to me

grave jolt Oct 25, 2020, 6:25 AM

#

I made use of this too 🙂

gleaming rover Oct 25, 2020, 6:25 AM

#

when I saw that most languages bind early I was like "WTF"

grave jolt Oct 25, 2020, 6:26 AM

#

It doesn't make sense to me specifically in a loop like this.

gleaming rover Oct 25, 2020, 6:26 AM

#

I suppose not

grave jolt Oct 25, 2020, 6:28 AM

#

So if the loop had its own scope, the lambda would refer to a new cell every time. But it probably is too narrow of a use case to actually implement block scopes with something like

for x in range(5):
    scoped x
    fs.append(lambda: x)

(because doing otherwise is a breaking change)

#

...and still doesn't get rid of the gotcha

raven ridge Oct 25, 2020, 6:29 AM

#

the loop kinda does have its own scope, though only for the loop variable...

#

x isn't usable after the loop ends (anymore)

grave jolt Oct 25, 2020, 6:29 AM

#

wdym?

#

!e

for x in range(5):
    ...
print(x)

fallen slateBOT Oct 25, 2020, 6:29 AM

#

@grave jolt :white_check_mark: Your eval job has completed with return code 0.

raven ridge Oct 25, 2020, 6:30 AM

#

ah, I'm mixing it up with exceptions - that's the one that changed

#

and comprehensions.

#

!e ```py
print([x for x in "abc"])
print(x)

fallen slateBOT Oct 25, 2020, 6:30 AM

#

@raven ridge :x: Your eval job has completed with return code 1.

001 | ['a', 'b', 'c']
002 | Traceback (most recent call last):
003 |   File "<string>", line 2, in <module>
004 | NameError: name 'x' is not defined

raven ridge Oct 25, 2020, 6:30 AM

#

in Python 2 that would've printed c.

grave jolt Oct 25, 2020, 6:30 AM

#

Yeah, a comprehension is a function call to an anonymous function with the iterable as an argument...

raven ridge Oct 25, 2020, 6:31 AM

#

and exceptions are the other one where the scope changed.

#

!e ```py
try:
1/0
except Exception as e:
exc = e
print(exc)
print(e)

fallen slateBOT Oct 25, 2020, 6:32 AM

#

@raven ridge :x: Your eval job has completed with return code 1.

001 | division by zero
002 | Traceback (most recent call last):
003 |   File "<string>", line 6, in <module>
004 | NameError: name 'e' is not defined

raven ridge Oct 25, 2020, 6:32 AM

#

in 2, that'd print "division by zero" twice.

smoky turret Oct 25, 2020, 6:33 AM

#

comprehensions actually had some weird behavior with yield up to 3.7

📎 unknown.png

#

now yielding is a syntax error

#

as for the block scope discussion, I havent thought about this example enough to say definitively, but given that you can do things like this, im not sure you really can have block scope in python without changing a lot of whats allowed

📎 unknown.png

#

assignment targets are super flexible

#

which really blurs the line of what would even count as a block level variable

grave jolt Oct 25, 2020, 6:50 AM

#

Hm, I didn't think about this 🤔

plain spindle Oct 25, 2020, 7:57 AM

#

is there any advantage to using @staticmethod over @classmethod?

smoky turret Oct 25, 2020, 7:58 AM

#

its nicer semantically, assuming its appropriate for the method

last pollen Oct 25, 2020, 7:58 AM

#

they both do different things, @staticmethod for basically associating a regular function (one that doesn't need a class instance) to a class, @classmethod for methods that use the class itself rather than instances of the class

slim plover Oct 25, 2020, 8:03 AM

#

anyone good with instagram api dm me i need help

grave jolt Oct 25, 2020, 8:04 AM

#

@slim plover This is a discussion channel, not a help channel. If you want to get help, see #❓｜how-to-get-help. If it doesn't break our rules, there is no reason to ask it in DM instead of here

plain spindle Oct 25, 2020, 8:08 AM

#

@last pollen i'm aware of their stated intent, however i don't see any disadvantage of just always using @classmethod, even when a @staticmethod would work too

#

like, the obvious advantage of using staticmethod is that you can do Class.method(x) instead of needing an instance. but this applies to classmethod too

slim plover Oct 25, 2020, 8:09 AM

#

fix error us a bot?

#

is*

smoky turret Oct 25, 2020, 8:10 AM

#

well yeah, staticmethod is basically exactly the same as classmethod, it just throws away the class param, so it provides strictly less info. But dont discount the semantic meaning that entails for users

teal yacht Oct 25, 2020, 8:10 AM

#

you're dismissing the intent tho

#

which is the biggest part

raven ridge Oct 25, 2020, 8:10 AM

#

@plain spindle if it doesn't need the class or an instance, then you should prefer just not making it part of the class at all. It should just be a global function.

grave jolt Oct 25, 2020, 8:10 AM

#

I officially failed the Turing test

plain spindle Oct 25, 2020, 8:10 AM

#

i disagree there. i prefer the organization benefit of associating it with the class, especially if it's a private helper

raven ridge Oct 25, 2020, 8:11 AM

#

If it's a private helper, make it a private global function instead. 🤷‍♂️

plain spindle Oct 25, 2020, 8:11 AM

#

ha, i bet you don't even use nested classes

#

nerd

smoky turret Oct 25, 2020, 8:11 AM

#

naw, having things be organized into the nice namespaces that are classes is nice

grave jolt Oct 25, 2020, 8:12 AM

#

Sometimes a function has to be in a class. For example, a method of a tree visitor/transformer if you never need self.

smoky turret Oct 25, 2020, 8:12 AM

#

"Namespaces are one honking great idea -- let's do more of those!"

teal yacht Oct 25, 2020, 8:12 AM

#

the zen of python went into the trash bin 25 years ago

raven ridge Oct 25, 2020, 8:12 AM

#

No, I don't think I've ever created a nested class in production code.

teal yacht Oct 25, 2020, 8:12 AM

#

it's no longer a relevant "argument"

smoky turret Oct 25, 2020, 8:13 AM

#

gonna say a hard no to that

plain spindle Oct 25, 2020, 8:13 AM

#

hmm… is overriding an instance method with a classmethod a breaking change

teal yacht Oct 25, 2020, 8:13 AM

#

shouldn't be as far as i can tell

smoky turret Oct 25, 2020, 8:13 AM

#

certainly an unusual maneuver

plain spindle Oct 25, 2020, 8:13 AM

#

fix error here is suggesting it with their NodeVisitor example

#

idk man, reading that, i would have to pause and check the docs, or else comment why i'm making it a classmethod and not an instance method

grave jolt Oct 25, 2020, 8:15 AM

#

Well, class methods are usually factory methods or something like that. When you need the class, but not the insrance (because sometimes you don't have an instance)

#

a class method can access other class methods of that class, unlike a static method

smoky turret Oct 25, 2020, 8:16 AM

#

only real times I've used classmethods were for alternative constructors

plain spindle Oct 25, 2020, 8:16 AM

#

i guess i just mean, if they removed staticmethod i'd be okay with that

#

i think it's a holdover from old-style classes anyway

#

thanks everyone

smoky turret Oct 25, 2020, 8:17 AM

#

not sure the 2.x 3.x class distinction is too relevant

plain spindle Oct 25, 2020, 8:17 AM

#

@smoky turret i saw a really cool example that combines zip() and dict loop target assignment to invert a dict

smoky turret Oct 25, 2020, 8:17 AM

#

Im pretty sure the math module uses basically a bunch of staticmethods

grave jolt Oct 25, 2020, 8:18 AM

#

those are ordinary functions, no?

smoky turret Oct 25, 2020, 8:18 AM

#

ah yeah, strike that

grave jolt Oct 25, 2020, 8:18 AM

#

random uses bound methods, which is a different thing

smoky turret Oct 25, 2020, 8:18 AM

#

mhm

#

@plain spindle im curious what this example is

plain spindle Oct 25, 2020, 8:19 AM

#

🐍 d = {1: 'a', 2: 'b', 3: 'c'}
🐍 i = {}
🐍 for k, i[k] in map(reversed, d.items()): pass
•• 
🐍 i
{'a': 1, 'b': 2, 'c': 3}

teal yacht Oct 25, 2020, 8:19 AM

#

cursed ps1

plain spindle Oct 25, 2020, 8:19 AM

#

i like it

#

i like my ps2 better though as my emoji font is a little annoying

#

mostly that it's ascii-character-width shorter than >>>

safe hedge Oct 25, 2020, 8:20 AM

#

If it's a private helper, make it a private global function instead. 🤷‍♂️
@raven ridge What about the case where its a private helper on an interface which gets new subclasses where the helper is specifically tied to that subclass implementation

raven ridge Oct 25, 2020, 8:22 AM

#

Then make it an instance method

safe hedge Oct 25, 2020, 8:23 AM

#

But why. If it doesn't ever need self

#

The add_arguments method here is prime candidate to actually be a staticmethod imo: https://github.com/django/django/blob/master/django/core/management/base.py

GitHub

django/django

The Web framework for perfectionists with deadlines. - django/django

raven ridge Oct 25, 2020, 8:24 AM

#

Just because it's an instance method doesn't mean you need to use self, and you can't know whether your subclass will need access to instance state to perform that method's duty, and people above were confused about the semantics of overloading one type of method with another, so forcing that on your users is a completely unnecessary maintenance burden

grave jolt Oct 25, 2020, 8:25 AM

#

speaking of cursed prompts 🙂

📎 unknown.png

safe hedge Oct 25, 2020, 8:25 AM

#

Wouldn't the implication of making it static be precisely that it shouldn't be using state?

raven ridge Oct 25, 2020, 8:27 AM

#

Then I don't understand the question. If the subclass override of the method wouldn't use any of the subclass's state (instance or class variables), then why would the subclass override of that method be different?

smoky turret Oct 25, 2020, 8:28 AM

#

The usecase of staticmethod is, in the real world, basically just the case where you have a bunch of functions that are vaguely related by meaning/context (though decidedly not by state) and you want to group them together. I cant imagine many cases where a "real" class would have a reasonable staticmethod

safe hedge Oct 25, 2020, 8:28 AM

#

Because it's doing something totally different? Look at the django example. The method is just an entrypoint to add extra arguments to a parser...

#

And the parser is passed and not accessed via self

raven ridge Oct 25, 2020, 8:29 AM

#

@smoky turret I agree completely, but that should be a module and someone is just being lazy.

smoky turret Oct 25, 2020, 8:30 AM

#

@raven ridge meh, in the case of wanting multiple different groups of functionality, sure you could have subpackages, but I dont think theres anything wrong with the class approach

sacred yew Oct 25, 2020, 8:30 AM

#

that sounds like java shit

#

where you can't have top level functions

raven ridge Oct 25, 2020, 8:32 AM

#

Look at the django example.
@safe hedge that example calls super with no arguments. That can't be done in a static method, because super needs to know the MRO, which it finds from the class or instance passed to the method that uses it

smoky turret Oct 25, 2020, 8:32 AM

#

lol gottem

safe hedge Oct 25, 2020, 8:33 AM

#

Does it call super?

#

I thought the only call was self.add_arguments(parser)

#

Which could easily be replaced with a staticmethod call

raven ridge Oct 25, 2020, 8:35 AM

#

def add_arguments(self, actions):
    super().add_arguments(self._reordered_actions(actions))```

safe hedge Oct 25, 2020, 8:36 AM

#

Ah we are looking at different add_arguments

#

That's the one on HelpFormatter. I'm talking about the one on BaseCommand

#

def add_arguments(self, parser):
        """
        Entry point for subclassed commands to add custom arguments.
        """
        pass

raven ridge Oct 25, 2020, 8:37 AM

#

Link to a line number next time 😋

smoky turret Oct 25, 2020, 8:37 AM

#

strikes me as unlikely that its gonna be a good idea to make it a static method regardless

#

to make something a staticmethod is to say definitely that it does not, and will never require any mutual state

#

which is why basically the only time it makes sense to do is, as previously said, when you got some truly seperate functions you want to group together

sacred yew Oct 25, 2020, 8:39 AM

#

Doesn't that explicitly say it's for the subclasses to override

safe hedge Oct 25, 2020, 8:39 AM

#

What's that got to do with it?

raven ridge Oct 25, 2020, 8:40 AM

#

The point I made earlier still stands. If this was a static method, subclasses would need to override it with a regular instance method. Which people find confusing.

smoky turret Oct 25, 2020, 8:40 AM

#

well, that decidedly violates the "knowing it will never require state" req @safe hedge

#

a static, abstract method is a very weird idea

#

no conceivable usecase I can come up with

grave jolt Oct 25, 2020, 8:42 AM

#

class Monoid:
    @staticmethod
    def zero(): ...

    def __add__(self, other): ...

but that's, um... esoteric

smoky turret Oct 25, 2020, 8:43 AM

#

god damn functional people

grave jolt Oct 25, 2020, 8:44 AM

#

Sorry, couldn't find a different example 😦

#

class IConcatenatableAndNeutralelementable:
    @staticmethod
    def zero(): ...

    def __add__(self, other): ...

better? 🙂

smoky turret Oct 25, 2020, 8:46 AM

#

better add something about functors, really get the functional people going

safe hedge Oct 25, 2020, 8:48 AM

#

The point I made earlier still stands. If this was a static method, subclasses would need to override it with a regular instance method. Which people find confusing.
@raven ridge Why would they?

raven ridge Oct 25, 2020, 8:58 AM

#

hmm… is overriding an instance method with a classmethod a breaking change
idk man, reading that, i would have to pause and check the docs, or else comment why i'm making it a classmethod and not an instance method
They are. 🤷

flat gazelle Oct 25, 2020, 8:59 AM

#

Doing that would violate LSP, since a subclass should not demand a different calling convention from a superclass, which it would do if you overrode staticmethod with a regular function

raven ridge Oct 25, 2020, 9:00 AM

#

Would it be observable to users of the class?

#

If it's a static method in the base class it can't be made an instance method on the subclass without violating Liskov. It could be made a class method. I think

#

Actually... Given that Liskov only says anything about how instances of the class behave, not the class itself, I think even overriding a static method with an instance one doesn't violate Liskov.

#

You wouldn't be able to call the method on the subclass without an instance, but I don't think Liskov requires that to be possible, since Liskov only deals in instances.

#

(that said, the very fact that it's not clear whether or not it violates LSP is itself a very good reason not to do it)

undone flame Oct 25, 2020, 10:18 AM

#

Because dict values aren't unique, for reversing a dict I ususally use something like:

[result[value].add(key) for k,v in input.items()]
return result
or
return {k:v for k,v in result.items()}```

mint forge Oct 25, 2020, 10:43 AM

#

In what circumstances or situations do we use @classmethod?

brave badger Oct 25, 2020, 10:43 AM

#

Alternative constructors are the main one

mint forge Oct 25, 2020, 10:43 AM

#

huh?

brave badger Oct 25, 2020, 10:45 AM

#

For example, if you have a class that models an API response e.g. from the YouTube API

class Video:
    def __init__(self, video_id, video_metadata):
        ...
```instead of passing that information by yourself, you can create a class method that reads that data directly from the JSON response
```python
class Video:
    def __init__(self, video_id, video_metadata):
        ...
    @classmethod
    def from_json(cls, data):
        ... # Do processing
        return cls(video_id, video_metadata)

mint forge Oct 25, 2020, 10:46 AM

#

mhm

unkempt rock Oct 25, 2020, 3:52 PM

#

How can I run a discord client with a proxy?

grave jolt Oct 25, 2020, 4:00 PM

#

@unkempt rock This is not a help channel. See #❓｜how-to-get-help.

#

...and I'm not sure there are legitimate uses for that.

hearty monolith Oct 25, 2020, 4:06 PM

#

Question: PEP 617 (accepted in Python 3.9) mentioned ```
The new proposed PEG parser contains the following pieces:

A parser generator that can read a grammar file and produce a PEG parser written in Python or C that can parse said grammar```So....one can just define their own version of Python(?) grammar now?

brave badger Oct 25, 2020, 4:16 PM

#

I believe it just means that the new PEG parser generator can use the existing grammar that Python uses

#

and that it's more flexible than it currently is

swift imp Oct 25, 2020, 4:41 PM

#

Heres a question, why cant they just make generators be iterable as many times as possible?

#

If they keep the original, they're still only accessing one element at a time..

grave jolt Oct 25, 2020, 4:47 PM

#

A generator is iterable as many times as you want.

#

!e

def forever():
    i = 0
    while True:
        yield i
        i += 1

generator = forever()

print(next(generator), end=" ")
print(next(generator), end=" ")

for i in generator:
    print(i, end=" ")
    if i == 7:
        break

for i in generator:
    print(i, end=" ")
    if i == 12:
        break
print()

fallen slateBOT Oct 25, 2020, 4:49 PM

#

@grave jolt :white_check_mark: Your eval job has completed with return code 0.

0 1 2 3 4 5 6 7 8 9 10 11 12

grave jolt Oct 25, 2020, 4:49 PM

#

@swift imp

#

It's just that the generator is a stateful object, and by iterating over it you change its state, as shown here ^
And you might exhaust the generator if it's finite. Then it will not have any more values to generate.

#

If you mean iterator, not generator, the answer is the same. An iterator can be a view on some iterable. It's stateful as well.

unkempt rock Oct 25, 2020, 5:28 PM

#

import sqlite3 # Builtin imports
import secrets

from typing import Optional # Direct element import from builtin

from utils.logger import logger # Local direct import

What would be the best way to organize these imports?

#

also, i think this channel is not the best for that

#

but it's related to import conventions

boreal umbra Oct 25, 2020, 5:28 PM

#

@unkempt rock you do stdlib, then a blank line, then other libraries, then a new line, and then imports from the same package

#

it's in pep8

unkempt rock Oct 25, 2020, 5:29 PM

#

i get a bit confused by imports with from

#

they must keep at the bottom with the local packages?

boreal umbra Oct 25, 2020, 5:30 PM

#

https://www.python.org/dev/peps/pep-0008/#imports

Python.org

PEP 8 -- Style Guide for Python Code

The official home of the Python Programming Language

#

if you're using pycharm, control + o will organize your imports

unkempt rock Oct 25, 2020, 5:31 PM

#

actually using vscode

#

but thanks anyways, i'll give a better read into the pep8 imports

reef otter Oct 25, 2020, 5:36 PM

#

You can use isort module for import formatting and black for code formatiing.

#

If you are using github then you can use restyled bot which will format code for you. 😎

molten onyx Oct 25, 2020, 5:41 PM

#

Hettinger posted some interesting results about the lru_cache decorator on twitter: https://twitter.com/raymondh/status/1320411457607983105

I am able to reproduce this but I genuinely have no idea why it is faster, does anyone have some insights into this?

Raymond Hettinger (@raymondh)

2/ Here are the timings:

$ python3.9 -m timeit -r11 -s 'def s(x):pass' 's(5)'
5000000 loops, best of 11: 72.1 nsec per loop

$ python3.9 -m timeit -r11 -s 'from functools import cache' -s 'def s(x):pass' -s 'c=cache(s)' 'c(5)'
5000000 loops, best of 11: 60.6 nsec per loop

#

Surely bytecode-wise it should be slower, since it's just a LOAD_CONST

#

I'm assuming it's something to do with CPython not running the "actual" python interpreter for C function implementations, but cheating somehow

#

(since you know C code cant be compiled into bytecode)

grave jolt Oct 25, 2020, 5:44 PM

#

...technically it can, but why 🙂

flat gazelle Oct 25, 2020, 5:48 PM

#

I would guess it is because cache[x] is faster since that class has slots, which regular functions do not.

uncut sage Oct 25, 2020, 7:26 PM

#

I think it's also because cached functions minimize the amount of work done by the interpreter

#

basically, the call opcode is never actually executed

#

functools.cache is great whenever you can leverage it

unkempt rock Oct 25, 2020, 7:36 PM

#

Hello folks. Can anybody think of a faster alternative to this:

#

sum(letters_scores[letter] for letter in all_hands)

boreal umbra Oct 25, 2020, 7:37 PM

#

@unkempt rock what are you doing that this isn't fast enough?

unkempt rock Oct 25, 2020, 7:38 PM

#

all_hands being a really, really, long list. letters_scores a dictionary such as: dict(q=10, z=10, a=1, etc)

#

@unkempt rock what are you doing that this isn't fast enough?
@boreal umbra I am computing the scores in JSON lists of 3+ million long strings.

boreal umbra Oct 25, 2020, 7:40 PM

#

I believe it would be faster if the data were in a structure like a pandas DataFrame, but putting all the data into a DataFrame if it isn't already would probably be the same speed as the line you gave.

#

you might see if pandas can get data out of a json

unkempt rock Oct 25, 2020, 7:41 PM

#

Unfortunately I can detect few duplicates among the words. I tested a slower alternative solution considering words lookups instead of letters, to take advantage of duplicates.

boreal umbra Oct 25, 2020, 7:41 PM

#

iteration in Python is slow, so libraries for crunching large quantities of data do the iteration in C.

unkempt rock Oct 25, 2020, 7:41 PM

#

I believe it would be faster if the data were in a structure like a pandas DataFrame, but putting all the data into a DataFrame if it isn't already would probably be the same speed as the line you gave.
@boreal umbra Of course, agreed. I am limited to the standard builtins. No imports.

boreal umbra Oct 25, 2020, 7:41 PM

#

I don't know of a solution, then.

unkempt rock Oct 25, 2020, 7:41 PM

#

Thanks anyway.

boreal umbra Oct 25, 2020, 7:42 PM

#

why do you have that constraint anyway?

unkempt rock Oct 25, 2020, 7:43 PM

#

Academic exercise.

boreal umbra Oct 25, 2020, 7:44 PM

#

in that case, I would emphasize readability, and your sum statement is very much that.

gloomy rain Oct 25, 2020, 7:44 PM

#

@unkempt rock You have to do this in Python too?

unkempt rock Oct 25, 2020, 7:44 PM

#

@boreal umbra I don't need to be readable in this case. I merely want to test the limits of the setup/language.

gloomy rain Oct 25, 2020, 7:45 PM

#

I wonder if it would be slightly faster to manually implement a function to map the letters to scores rather than use a dictionary to do the lookup.

unkempt rock Oct 25, 2020, 7:45 PM

#

@gloomy rain Yes, Python and no mas. Nothing else.

spark magnet Oct 25, 2020, 7:45 PM

#

@unkempt rock maybe you already mentioned this: why does it need to be faster?

unkempt rock Oct 25, 2020, 7:45 PM

#

I wonder if it would be slightly faster to manually implement a function to map the letters to scores rather than use a dictionary to do the lookup.
@gloomy rain Yeah ... but what could possibly beat a dictionary lookup? A switch statement?

gloomy rain Oct 25, 2020, 7:46 PM

#

@unkempt rock Just a sequence of if else

#

It would be a very very slight improvement, if any, though

unkempt rock Oct 25, 2020, 7:46 PM

#

@unkempt rock maybe you already mentioned this: why does it need to be faster?
@spark magnet Somebody mentioned there's a faster alternative to my code. So I am looking for it!

boreal umbra Oct 25, 2020, 7:46 PM

#

@gloomy rain I think using a dict would be one call to hash and one call to __eq__, whereas chained if-else would be multiple calls to __eq__

gloomy rain Oct 25, 2020, 7:47 PM

#

Hm, right

#

True

spark magnet Oct 25, 2020, 7:47 PM

#

all_hands is a list of single letters?

boreal umbra Oct 25, 2020, 7:47 PM

#

it's probably unlikely that you'd get a collision if it's just ABCDF as keys

gloomy rain Oct 25, 2020, 7:47 PM

#

Yeah, for sure.

#

Nevermind then.

unkempt rock Oct 25, 2020, 7:47 PM

#

@gloomy rain Perhaps I could analyse the most frequent letters in the sample data and break out of a carefully constructed series of if ... a would go first, e after, etc.

gloomy rain Oct 25, 2020, 7:48 PM

#

Sounds unlikely.

rancid hull Oct 25, 2020, 7:48 PM

#

In need of a competent discord bot developer who would be interested in an exciting new project/business venture. Please contact me if interested

unkempt rock Oct 25, 2020, 7:48 PM

#

it's probably unlikely that you'd get a collision if it's just ABCDF as keys
@boreal umbra Absolutely. I tested whether using dictionaries get with a default value was faster than the index notation (perhaps no missing key exception check) ... but it's not.

boreal umbra Oct 25, 2020, 7:49 PM

#

@rancid hull this server isn't a place to solicit paid help. Take a look at #career-advice for a link to the official Python job board.

rancid hull Oct 25, 2020, 7:49 PM

#

appreciate it 😄

unkempt rock Oct 25, 2020, 7:49 PM

#

all_hands is a list of single letters?
@spark magnet It is. I joined a list of strings to make just one big list of characters. The join operation is incredibly fast and it helps as I have to count the number of letters (len)

spark magnet Oct 25, 2020, 7:50 PM

#

@unkempt rock perhaps there isn't a faster way to do the sum you showed us, but there is a faster way to do the larger problem that it's a part of?

unkempt rock Oct 25, 2020, 7:52 PM

#

@unkempt rock perhaps there isn't a faster way to do the sum you showed us, but there is a faster way to do the larger problem that it's a part of?
@spark magnet I profiled the whole code and >90% of the time is spent on the sum line. But yes, perhaps I could prepare the setup better. I did explore several alternatives. The initial list of list of strings was slow to operate on. The join statement amounts to 2% of execution time.

spark magnet Oct 25, 2020, 7:53 PM

#

@unkempt rock ok, hard to comment without seeing the original problem

unkempt rock Oct 25, 2020, 7:53 PM

#

@spark magnet Understandable. Thanks though.

boreal umbra Oct 25, 2020, 7:53 PM

#

@unkempt rock well, what else is the code doing? because even though it's one line, it sounds like what it was doing was the biggest job to be done anyway.

unkempt rock Oct 25, 2020, 7:56 PM

#

This is the relevant code, all else is not very relevant and can't be optimised:

#

_letters_scores = dict(
        q=10, z=10,
        j=8, x=8,
        k=5,
        f=4, h=4, v=4, w=4, y=4,
        b=3, c=3, m=3, p=3,
        d=2, g=2,
        e=1, a=1, i=1, o=1, n=1, r=1, t=1, l=1, s=1, u=1)

    @profile
    def score_letters(self):
        letters_scores = self._letters_scores           # local variable caching helps with frequent lookups
        all_hands = ''.join(self.hands)
        return len(all_hands), sum(letters_scores[letter] for letter in all_hands)

#

I was surprised to learn that the letters_scores local assignment actually helps!

flat gazelle Oct 25, 2020, 8:06 PM

#

try sum(map(self._letters_scores.__getitem__, all_hands)), and compare ''.join with itertools.chain.from_iterable

unkempt rock Oct 25, 2020, 8:15 PM

#

try sum(map(self._letters_scores.__getitem__, all_hands)), and compare ''.join with itertools.chain.from_iterable
@flat gazelle You've create a monster. It's way faster than the standard [] dictionary lookup + comprehension. I am reading up on why that is the case. Thanks a bunch!

boreal umbra Oct 25, 2020, 8:18 PM

#

@hoary kite try asking in #data-science-and-ml or open a help channel. There are instructions for that on #❓｜how-to-get-help

unkempt rock Oct 25, 2020, 8:30 PM

#

The map generator seems to be way faster than for letter in all_hands and that makes all the difference. Thanks again, @flat gazelle

flat gazelle Oct 25, 2020, 8:31 PM

#

map is only faster for non-python functions IIRC

unkempt rock Oct 25, 2020, 8:34 PM

#

map is only faster for non-python functions IIRC
@flat gazelle I don't fully understand. What do you mean by non-python functions? Builtin functions such as sum or __getitem__ but not ones I define?

smoky turret Oct 25, 2020, 8:35 PM

#

from https://wiki.python.org/moin/PythonSpeed/PerformanceTips

📎 unknown.png

hoary orbit Oct 25, 2020, 8:37 PM

#

anyone can help me with a problem with json

unkempt rock Oct 25, 2020, 8:38 PM

#

Thanks @smoky turret . I had read that, although it seems somewhat dated.

smoky turret Oct 25, 2020, 8:38 PM

#

yeah

hoary orbit Oct 25, 2020, 8:39 PM

#

yeah
@smoky turret how i can extract data from a big json?

smoky turret Oct 25, 2020, 8:39 PM

#

not a help channel, but whats wrong with the json module?

hoary orbit Oct 25, 2020, 8:40 PM

#

not a help channel, but whats wrong with the json module?
@smoky turret i dont know how extract a value from a json because is so big

smoky turret Oct 25, 2020, 8:41 PM

#

ask in #python-discussion or claim a help channel, im busy

magic python Oct 25, 2020, 9:51 PM

#

i almost never use generators 🤔 feel that i'm missing out on something

crystal kindle Oct 25, 2020, 10:08 PM

#

hey all

#

I have a position, scale, and a set of points I want to make a worldTransform matrix from
origin

origin+normal = Z axis

origin + (origin- ((v2+v1)/2) ) = X axis

#

https://docs.blender.org/api/blender_python_api_2_78_release/mathutils.html#mathutils.Matrix

#

I don't understand how to use the data I have to produce a world_transform matrix

#

(scale+rot+pos)

signal tide Oct 25, 2020, 10:14 PM

#

what advantage does (more-)itertools provide compared to creating generators manually?

feral cedar Oct 25, 2020, 10:18 PM

#

other than you don't have to make them manually?

digital mist Oct 25, 2020, 10:18 PM

#

i too have a question
i have beginner-intermediate python experience
id like to make an app on my phone thatll have logs and notifications and daily checklists.

trying to research android dev, is it worth it to use python to achieve this or should i try using a different language? idk how supported python is on android

signal tide Oct 25, 2020, 10:18 PM

#

ya I'm just wondering if there's a performance advantage

cloud crypt Oct 25, 2020, 10:19 PM

#

with itertools, there is

feral cedar Oct 25, 2020, 10:19 PM

#

i believe kivy can be used to create android apps @digital mist . java and kotlin are probably the most common languages for android app dev

digital mist Oct 25, 2020, 10:19 PM

#

is kivy available for those languages?

feral cedar Oct 25, 2020, 10:19 PM

#

no

digital mist Oct 25, 2020, 10:20 PM

#

how does exporting kivy to android work?

feral cedar Oct 25, 2020, 10:20 PM

#

i have no idea, try asking in #user-interfaces

digital mist Oct 25, 2020, 10:20 PM

#

ty

signal tide Oct 25, 2020, 10:20 PM

#

@cloud crypt do you happen to know why? (or have any metrics)

flat gazelle Oct 25, 2020, 10:21 PM

#

Itertools are written in C

smoky turret Oct 25, 2020, 10:22 PM

#

I love itertools

cloud crypt Oct 25, 2020, 10:24 PM

#

they are written in C and they should be several times faster

feral cedar Oct 25, 2020, 10:24 PM

#

what character did you type first?

#

!charinfo

fallen slateBOT Oct 25, 2020, 10:25 PM

#

Character Info

\ufffc : OBJECT REPLACEMENT CHARACTER -

feral cedar Oct 25, 2020, 10:25 PM

#

nice

magic python Oct 25, 2020, 11:35 PM

#

i looked at moreitertools recently and didn't see too much usage for myself

#

most of it seemed as though it was a listcomp or whatever, but maybe it's bc i don't use generators enough

boreal umbra Oct 25, 2020, 11:36 PM

#

@magic python my favorite thing in more itertools is the chunking function

magic python Oct 25, 2020, 11:37 PM

#

yeah you said that! I need to try it out, i did think it looked interesting

#

you use it much?

boreal umbra Oct 25, 2020, 11:37 PM

#

I've used it much, but I've helped several people implement the same functionality by hand

#

it's one of the most obvious things that Python doesn't have in the stdlib, I think.

magic python Oct 25, 2020, 11:38 PM

#

hrm - a lot of this i think i don't need because i'm always in pandas as well

swift imp Oct 25, 2020, 11:48 PM

#

Their groupby function is pretty nice too

smoky turret Oct 25, 2020, 11:51 PM

#

I've never actually used more-itertools, and I'd probably just copy/paste something from it instead of adding it as a dependancy, but I can appreciate its existence

#

eh its under MIT, guess no copy paste then

peak spoke Oct 25, 2020, 11:56 PM

#

mit is pretty much just copy paste

smoky turret Oct 25, 2020, 11:58 PM

#

you'd have to include the license with it

#

at that point I'd just install it

#

its a lightweight dependency anyways

#

I think, anyways

#

its pure python right?

peak spoke Oct 25, 2020, 11:59 PM

#

yes

crystal kindle Oct 26, 2020, 12:15 AM

#

got it!

sacred yew Oct 26, 2020, 12:16 AM

#

yeah why isn't grouper in the stdlib already

#

it's the only itertools recipe I actually use

crystal kindle Oct 26, 2020, 12:18 AM

#

ittertools sounds nice

#

bulk operations ?

#

like SIMD kinda?

teal yacht Oct 26, 2020, 12:24 AM

#

No, there is no SIMD in itertools

#

It's a utility module to do a bunch of stuff with iterables

pastel steppe Oct 26, 2020, 12:52 AM

#

📎 66166696259366912.png

feral cedar Oct 26, 2020, 12:53 AM

#

are you trying to write it in python?

pastel steppe Oct 26, 2020, 12:53 AM

#

ye

boreal umbra Oct 26, 2020, 12:53 AM

#

@pastel steppe probably a question for #data-science-and-ml

boreal umbra Oct 26, 2020, 2:13 AM

#

what if t.List[t.Tuple[str, str, str]] was t.List[t.Tuple[str * 3]]

#

would probably be problematic for parsing unless the parser treated it as a special case

teal yacht Oct 26, 2020, 2:17 AM

#

ew no, that's a terrible edge case

crystal pebble Oct 26, 2020, 2:19 AM

#

Seems like a good place for an alias or generics with constraints though

boreal umbra Oct 26, 2020, 2:19 AM

#

@crystal pebble it would be if not for the fact that I only use it once

#

it exists temporarily and becomes a dataframe

peak spoke Oct 26, 2020, 2:33 AM

#

That doesn't look too good imo, if you have tuples huge enough that it'd make sense to use the mult then perhaps it'd make sense to restructure or at least make it an alias; would love some more flexibility with list though

crystal pebble Oct 26, 2020, 2:34 AM

#

The closest I found is:
To specify a variable-length tuple of homogeneous type, use literal ellipsis, e.g. Tuple[int, ...]. A plain Tuple is equivalent to Tuple[Any, ...], and in turn to tuple.

I don't know much about the type system, but maybe you can use something hacky using *args

# This makes each positional arg and each keyword arg a "str" def call(self, *args: str, **kwargs: str) -> str: request = make_request(*args, **kwargs) return self.do_api_query(request)```

#

But at that point you're just making things harder to read

raven ridge Oct 26, 2020, 2:45 AM

#

Maybe an unpopular opinion, but: typing is most valuable for the public API of a module. Within a module's implementation, typing seems to require a lot of work for very little payoff. It does a subset of what unit tests do, and a proper unit test suite is much more valuable.

boreal umbra Oct 26, 2020, 2:46 AM

#

@raven ridge I use them for the signature of any function/method that I anticipate someone else will use, and then I only sprinkle them internally where I think they're helpful for someone trying to understand the implementation.

raven ridge Oct 26, 2020, 2:47 AM

#

That's pretty much my strategy, too.

boreal umbra Oct 26, 2020, 2:47 AM

#

in fact, this is the only line in that function that uses them: rows: t.List[t.Tuple[str, str, str]] = []

#

I only did it because the list starts out as empty.

peak spoke Oct 26, 2020, 2:49 AM

#

Unless it's something really complicated to do (getting easier as the typing peps get implemented), I prefer to hint everything

boreal umbra Oct 26, 2020, 2:50 AM

#

@peak spoke for function signatures, or assignment expressions as well?

crystal pebble Oct 26, 2020, 2:51 AM

#

I use them for my sanity since it's one less thing to worry about lemon_sentimental

raven ridge Oct 26, 2020, 2:51 AM

#

It's literally one more thing to worry about

peak spoke Oct 26, 2020, 2:52 AM

#

Well, with properly typed functions expressions don't need many hints, but also expressions if it's something larger in scope where the name is not sufficient

safe hedge Oct 26, 2020, 2:52 AM

#

Maybe an unpopular opinion, but: typing is most valuable for the public API of a module. Within a module's implementation, typing seems to require a lot of work for very little payoff. It does a subset of what unit tests do, and a proper unit test suite is much more valuable.
@raven ridge Strongly agree

crystal pebble Oct 26, 2020, 2:53 AM

#

Do you mean writing the hint? That's not a big deal at all

raven ridge Oct 26, 2020, 2:53 AM

#

Writing it, and maintaining it over time, yeah.

peak spoke Oct 26, 2020, 2:54 AM

#

I do get a bit angry with libs that don't have hints and I have to look into their source for the types nowadays

raven ridge Oct 26, 2020, 2:54 AM

#

typing private functions is extra work, makes for more verbose code, and add very little value - especially considering the you should have unit tests confirming that every type you want to be handled actually works as you expect.

safe hedge Oct 26, 2020, 2:54 AM

#

They can get really unwieldy and then you find yourself defining a custom type which you of course have to place/import

crystal pebble Oct 26, 2020, 2:54 AM

#

To be fair, Python is really weak in a lot of ways so it makes sense that it can become an issue

#

It'd be nice if you could add more constraints to things

safe hedge Oct 26, 2020, 2:55 AM

#

Doesn't that defeat the point of being dynamically typed though

crystal pebble Oct 26, 2020, 2:55 AM

#

No, it just gives you the option to make some guarantees when you want them

safe hedge Oct 26, 2020, 2:56 AM

#

Adding hard constraints upfront is antithetical to python's design

raven ridge Oct 26, 2020, 2:57 AM

#

typing isn't the way to add more constraints. isinstance checks and the like are.

#

typing is ignored at runtime, and constraints should be enforced at runtime

crystal pebble Oct 26, 2020, 3:00 AM

#

Maybe you guys are right. OOP requires its own way of thinking and I suck at it

#

And dynamic typing too

safe hedge Oct 26, 2020, 3:01 AM

#

OOP is neither here nor there with regards to constraints on types

crystal pebble Oct 26, 2020, 3:05 AM

#

Here's a code snippet from an old project. TBH, that's still nowhere near making me happy since there's a couple of things left to guarantee lemon_sentimental

📎 Screenshot_20201020-230639.png

#

Is there an easy way to refine things like that in Python? Expanding attributes, for example

raven ridge Oct 26, 2020, 3:07 AM

#

Given that the Python interpreter does not check arguments for consistency with declared types at runtime, I don't much see the point.

crystal pebble Oct 26, 2020, 3:07 AM

#

So that if you have an enum with data (locations in a game, for example) you can just the number of elements as an upper bound dynamically

crystal pebble Oct 26, 2020, 3:25 AM

#

Also, the more I read and learn the more it seems that C and C++ were the problem and not OOP

Quick question though z what does it mean to for something to only be "available on the class"? Does that mean only the class can access it

#

__members__ is a read-only ordered mapping of member_name:member items. It is only available on the class.

raven ridge Oct 26, 2020, 3:27 AM

#

It's not an instance attribute, it's only a class attribute.

#

given foo = Foo(), you can do Foo.__members__ but not foo.__members__

crystal pebble Oct 26, 2020, 3:28 AM

#

Ah, okay. Thanks

raven ridge Oct 26, 2020, 3:28 AM

#

Also, the more I read and learn the more it seems that C and C++ were the problem and not OOP
I'm not sure what this refers to. C isn't even an OOP language. C++ is a multi-paradigm language, like Python is - not pure OOP.

crystal pebble Oct 26, 2020, 3:29 AM

#

NM, I'm just gonna stop talking. New meds, two of of sleep in as many days. Sorry, good night

prisma star Oct 26, 2020, 4:15 AM

#

programming in c is like sleeping in the middle of a highway. It's not a safe feeling

#

-my systems prof

open plaza Oct 26, 2020, 6:29 AM

#

Can anybody please help to start contributing to python language?

#

Some pointer would be good?

gleaming rover Oct 26, 2020, 6:29 AM

#

Can anybody please help to start contributing to python language?
@open plaza what do you mean

smoky turret Oct 26, 2020, 6:30 AM

#

https://www.youtube.com/watch?v=voXVTjwnn-U

YouTube

SF Python

Raymond Hettinger, "Being a Core Developer in Python", PyBay2016

PyBay 2016 Keynote

What I've learned from being a maintainer and core developer for the past 15 years. Thoughts on channeling Guido, stability, hyper-generalization, Sturgeon's law and egativity, evaluating submissions, inability to predict the future, user centric design, tr...

▶ Play video

open plaza Oct 26, 2020, 6:30 AM

#

Good Morning, means contributing to open source

#

developing documentation

sacred yew Oct 26, 2020, 6:30 AM

#

isn't there a developers guide somewhere

open plaza Oct 26, 2020, 6:30 AM

#

or issue fixes

smoky turret Oct 26, 2020, 6:30 AM

#

I think so

#

https://devguide.python.org/

open plaza Oct 26, 2020, 6:31 AM

#

Thanks

smoky turret Oct 26, 2020, 6:31 AM

#

perhaps best foot in the door would be find some docs to cleanup/improve

open plaza Oct 26, 2020, 6:32 AM

#

Ok

smoky turret Oct 26, 2020, 6:32 AM

#

👍

tribal token Oct 26, 2020, 1:21 PM

#

Anyone knowing a good way to encode chinese characters and western characters with on encoding?

boreal umbra Oct 26, 2020, 1:23 PM

#

@tribal token that's probably a question for a help session. See #❓｜how-to-get-help. Strings are unicode by default if that matters.

tribal token Oct 26, 2020, 1:24 PM

#

ok. I will try that. I have problems with encoding in the cryptography library.

grave jolt Oct 26, 2020, 1:43 PM

#

@peak spoke

I do get a bit angry with libs that don't have hints and I have to look into their source for the types nowadays
Have you seen the source of motor?

#

It doesn't have type hints, and looking into the source doesn't help

peak spoke Oct 26, 2020, 1:52 PM

#

Last lib I had problems with was bs4 which was somewhat frustrating to work with as the source code is all over the place

boreal umbra Oct 26, 2020, 2:25 PM

#

Is there a way package maintainers usually keep track of changes they're going to make when they increase the bottom supported version?

gleaming rover Oct 26, 2020, 2:56 PM

#

Is there a way package maintainers usually keep track of changes they're going to make when they increase the bottom supported version?
@boreal umbra can you elaborate? I feel like I don't fully understand

boreal umbra Oct 26, 2020, 2:57 PM

#

@gleaming rover I'm working on a library (by myself) and because my uni refuses to upgrade past 3.7 (and sometimes they won't upgrade past 3.6) there are features from 3.8 and 3.9 that I can't use

#

but eventually things that are legal in 6 and 7 will be deprecated

#

for example, once 3.9 becomes the oldest supported version, I'll need to change expressions like t.List[str] to be list[str]

#

because by the time 3.9 is the oldest supported version, I'd want to be ready for when t.List[str] is deprecated.

spark magnet Oct 26, 2020, 3:00 PM

#

deprecated doesn't mean it stops working

boreal umbra Oct 26, 2020, 3:01 PM

#

another example, once I stop supporting 3.7, I can remove a dependency and use functools.cached_property

#

point being, I want to have a list of changes I want to make for the first version that stops supporting a given python version, and I'm wondering if there's a standard practice for that. Should it be a github issue or a document in the repo, for example?

visual shadow Oct 26, 2020, 3:03 PM

#

So you're basically asking if there's a good way to keep track of code that you know will be marked as depreciated, as a way to make it future proof?

boreal umbra Oct 26, 2020, 3:05 PM

#

@visual shadow I wasn't planning to keep track of specific parts of the code that would need to be changed, just general statements like "switch the generics" or "remove this library as a dependency and use functools"

gleaming rover Oct 26, 2020, 3:06 PM

#

point being, I want to have a list of changes I want to make for the first version that stops supporting a given python version, and I'm wondering if there's a standard practice for that. Should it be a github issue or a document in the repo, for example?
@boreal umbra this basically sounds like a more specific version of "how to write a changelog"

#

or did I get you wrong

boreal umbra Oct 26, 2020, 3:07 PM

#

If a change log can be something where you describe changes that you're going to make, then yes

#

I've never heard of that

gleaming rover Oct 26, 2020, 3:07 PM

#

well, a proposed changelog, I guess

#

I feel like there should be a rough correspondence between what's in your changelog and your Git commits (assuming you use Git, of course)

#

not sure if that's diverging from your original intention though

visual shadow Oct 26, 2020, 3:09 PM

#

Interesting question, I don't know if there's a formal way of doing this.

boreal umbra Oct 26, 2020, 3:09 PM

#

well, the goal is to have it written down what changes I will make years in the future, since I'm not likely to remember that one of my dependencies is made redundant by 3.8, for example.

visual shadow Oct 26, 2020, 3:10 PM

#

Yeah, I think something as simple as commiting a documentation file for this should suffice. Just not something I've ever seen before

gleaming rover Oct 26, 2020, 3:10 PM

#

that sounds like a roadmap

boreal umbra Oct 26, 2020, 3:11 PM

#

roadmap sounds like it could be it

#

thanks!

gleaming rover Oct 26, 2020, 3:13 PM

#

👋

sacred tinsel Oct 26, 2020, 3:15 PM

#

with github specifically, you can make an issue which describes what needs to be done, and assign it to a milestone

#

looking at the milestone for a specific release, you can then see all the issues that you wanted to complete by then

boreal umbra Oct 26, 2020, 3:16 PM

#

@sacred tinsel oh, that's pretty cool

#

I'd probably go with something like that if it were collaborative.

sacred tinsel Oct 26, 2020, 3:17 PM

#

you can use github issues even for private / personal projects, I do

#

but you could probably have a similar system with e.g. a trello board, create a list of cards for each future release

#

or a tag for each release

#

I think what you're looking for is creating some kind of a ticket that can be assigned to a specific category or group, so any tagging system should work

spiral willow Oct 26, 2020, 3:29 PM

#

Github has Kanban boards

#

that you can wire to issues

#

They call them "Projects"

sacred tinsel Oct 26, 2020, 4:22 PM

#

I just had this thought - would there be any issue with using the underscore thousands separator for the repr of ints?
e.g.:

>>> repr(10000)
'10_000'

#

since that would be a valid int literal with much better readability, although afaik there are some cultural differences in the way separators are used

grave jolt Oct 26, 2020, 4:24 PM

#

Well...

#

if print is unchanged, it my be fine

#

Because print can be used to pump the data to another program that probably doesn't really like 10_000

#

with |, that is

sacred tinsel Oct 26, 2020, 4:25 PM

#

ah true

grave jolt Oct 26, 2020, 4:26 PM

#

it also might be a bi confusing to beginners, because repr is used for the REPL

boreal umbra Oct 26, 2020, 4:27 PM

#

@sacred tinsel I personally would like that but I'm not sure how universal separating every third decimal is

#

I don't want to diverge of kwzrd's topic if we're not done with it but are pandas/numpy doing anything to make type hinting with their types more robust?

#

like specifying the shape of a matrix?

grave jolt Oct 26, 2020, 4:44 PM

#

It was discussed on the stream that more cool types may be going to be added to typing.

#

Specifying the shape of a matrix is only feasible if you never do anything other than get/set rows, get/set columns, get/set elements, comparing two matrices, or zipping two matrices (doing something for a pair of elements in each matrix).

#

You can also Add/remove a single row/column at a time if you use recursively defined naturals in types

#

But gluing two matrices together will need something like (Matrix[A, N1, M], Matrix[A, N1, M]) -> Matrix[A, N1+N2, M]

teal yacht Oct 26, 2020, 4:55 PM

#

I just had this thought - would there be any issue with using the underscore thousands separator for the repr of ints?
e.g.:
>>> repr(10000)
'10_000'

@sacred tinsel A bit late, but you can do "{:_}".format(1000000)

boreal umbra Oct 26, 2020, 4:56 PM

#

!e print(f'{1000000000:_}')

fallen slateBOT Oct 26, 2020, 4:56 PM

#

@boreal umbra :white_check_mark: Your eval job has completed with return code 0.

1_000_000_000

boreal umbra Oct 26, 2020, 4:56 PM

#

ayyy

sacred tinsel Oct 26, 2020, 4:57 PM

#

yea, I meant the repr of the int type specifically

teal yacht Oct 26, 2020, 4:57 PM

#

(similar to {:,})

sacred yew Oct 26, 2020, 5:24 PM

#

repr is supposed to be unambiguous

#

that means it shouldn't confuse people that dont know what the thousands separator is in python

teal yacht Oct 26, 2020, 6:05 PM

#

yeah, if readability is the concern, you should use str and or format

sacred yew Oct 26, 2020, 6:10 PM

#

and not everyone would agree that str for an int needs thousands separators

#

so better to leave it up to the programmer

#

because then there wouldnt be any method to get the current format

#

if you change str to use seperators

manic arch Oct 26, 2020, 6:29 PM

#

repr is supposed to be unambiguous
@sacred yew also, preferably, the output of repr should be suitable to put into eval() to create the exact same object again. if that is not possible, you should preferably return the <Foo object at 0x....> thing you often see when you print stuff

#

where 0x... is the address you can get via id()

#

but i believe that that is the default behavior of a non overridden repr already anyway 🙂

spice pecan Oct 26, 2020, 7:51 PM

#

It is, yeah

lime fractal Oct 26, 2020, 8:21 PM

#

hi

candid rose Oct 26, 2020, 9:33 PM

#

#game-development

grave jolt Oct 26, 2020, 10:21 PM

#

@elfin river This is not a help channel. See #❓｜how-to-get-help

#

We will not help you with bypassing captcha, though.

#

!rule 5

fallen slateBOT Oct 26, 2020, 10:22 PM

#

Rules

5. Do not provide or request help on projects that may break laws, breach terms of services, be considered malicious or inappropriate. Do not help with ongoing exams. Do not provide or request solutions for graded assignments, although general guidance is okay.

grave jolt Oct 26, 2020, 10:22 PM

#

And don't post links to resources like that @tardy mason, see ^ as well

smoky turret Oct 27, 2020, 12:12 AM

#

also, a thousands seperator is not even consistent across the world https://youtu.be/0j74jcxSunY?t=383

YouTube

Computerphile

Internationalis(z)ing Code - Computerphile

Audible free book: http://www.audible.com/computerphile
Catering for a global audience is difficult, Tom takes us through a 'timezones' style explanation of the things you need to keep in mind when internationalising your code.
This video features Tom Scott - more from him at:...

▶ Play video

halcyon trail Oct 27, 2020, 1:11 AM

#

How does one define a variadic generic class in python?

boreal umbra Oct 27, 2020, 1:12 AM

#

@halcyon trail what's variadic?

halcyon trail Oct 27, 2020, 1:12 AM

#

It means it has an arbitrary number of type parameters

#

for example, Tuple, Union, Callable

#

well Callable perhaps has a list of type parameters, so that's a bad example

boreal umbra Oct 27, 2020, 1:13 AM

#

so like a function with *args or **kwargs in the signature?

spark magnet Oct 27, 2020, 1:13 AM

#

@halcyon trail you want to pass arbitrary number of parameters? Or type parameters?

halcyon trail Oct 27, 2020, 1:18 AM

#

@spark magnet type parameters

#

so basically imagine something like this

#

class foo(typing.Generic[?]):
    data: typing.Union[?]

spark magnet Oct 27, 2020, 1:19 AM

#

what would that mean?

halcyon trail Oct 27, 2020, 1:19 AM

#

where the ? means, I don't know what to put in here, but its' the same idea

#

that means that if I have an instance of foo[int, str]

#

called say f

#

then f.data has type Union[int, str]

#

and so on

grave jolt Oct 27, 2020, 1:22 AM

#

@halcyon trail You can do U = TypeVar("U"), define Foo as class Foo(Generic[U]), and then use Foo[Union[int, str, str]]. I don't think it's possible to use type varargs now.

halcyon trail Oct 27, 2020, 1:34 AM

#

@grave jolt ah that's unfortunate

#

though I'm not that surprised

#

i guess even a list would be better?

#

So it would be Foo[[int, str, str]]

#

is there a way to do that?

raven ridge Oct 27, 2020, 1:39 AM

#

You could do that with 3 separate TypeVar's...

#

Realistically, your users are going to need casts or isinstance checks whenever they access that Union, so you may as well just declare it as Any instead.

fading trellis Oct 27, 2020, 1:58 AM

#

Hello, I have some questions about using yFinance. I have the code ready, is this the correct place to ask for help?

halcyon trail Oct 27, 2020, 2:00 AM

#

@raven ridge well,. This is a simplification of what I need it for

grave jolt Oct 27, 2020, 2:00 AM

#

@fading trellis Is yFinance scraping Yahoo? Or is it accessing an API?

halcyon trail Oct 27, 2020, 2:00 AM

#

And doing it with three type vars.isnt a solution, what if I only want to pass 1,.or 2,.or 4,. Etc

grave jolt Oct 27, 2020, 2:01 AM

#

@fading trellis Either way, see #❓｜how-to-get-help. This is a discussion channel, not a help channel.

fading trellis Oct 27, 2020, 2:01 AM

#

@grave jolt scaping yahoo.

grave jolt Oct 27, 2020, 2:02 AM

#

Then it probably breaks the ToS of Yahoo, so you can't get help with that on this server; but you can read them and see whether it does.

fading trellis Oct 27, 2020, 2:02 AM

#

well, I guess I need to go to the helping channel

#

I was just trying to find out how to get 4 hours data instead of 1 day data

#

couldn't find any answer on google haha

grave jolt Oct 27, 2020, 2:03 AM

#

Well, if it breaks ToS, that's a no-no here.

fading trellis Oct 27, 2020, 2:05 AM

#

well, I don't think so because yahoo do allow to download historical data but only for 1 day but not 4 hours...

#

but I wasn't sure so ill look somewhere else I guess

#

anyone know where I can get helps for my question?

grave jolt Oct 27, 2020, 2:06 AM

#

I already told you to see #❓｜how-to-get-help

fading trellis Oct 27, 2020, 2:07 AM

#

right, I mean other places beside discord

#

I tried stackoverflow but people on there kinda sucks

raven ridge Oct 27, 2020, 2:08 AM

#

And doing it with three type vars.isnt a solution, what if I only want to pass 1,.or 2,.or 4,. Etc
@halcyon trail that's going back to your earlier question - I don't think there's a way to make it variadic. I don't believe you can create a generic type that doesn't take a fixed number of arguments with the Python static typing system.

gleaming rover Oct 27, 2020, 2:09 AM

#

@raven ridge well,. This is a simplification of what I need it for
@halcyon trail what do you need it for

#

sounds interesting TBH

halcyon trail Oct 27, 2020, 2:09 AM

#

yeah it appears not unfortunately

#

well, what I need is actually pretty simple, I'll probably just define this as a class and overloaded the operator[] in its metaclass myself

#

what I need it for is basically I want to create a type annotation

#

actually, ugh, my approach prob doesn't work.

#

Anyhow what I want is to create a type annotation that is similar to a Union, but different, for the purposes of some generic code I have

#

@dataclass
class foo:
    x: Union[int, str]
    y: DefaultUnion[int, str]

#

so I have generic code that can deserialize dataclasses automatically from json

#

The way it works for something like Union is that in the corresponding place in the json, there has to be an entry __type__ that specifies which of the entries in the Union it contains data for

grave jolt Oct 27, 2020, 2:11 AM

#

You can define a linked list of types, like Cons[int, Cons[str, Nil]] somehow, but that's pretty esoteric

halcyon trail Oct 27, 2020, 2:12 AM

#

this works well in my code and i'm happy with it

rotund yew Oct 27, 2020, 2:12 AM

#

Hey, if I want to make a class that has many arguments, what will be the best way to do it so that when I make the objects later on (that will also quite many), so that I don't really have to memorize the argument orders? and is it going to be effective if I'll add let's say 15 - 20 objects with this class? So let's say I want to make a class of BuildingMaterial that will have these args:

class Material():
    """name, material type, standard dimension, usage, thermal           conductivity, density, finishing, connection"""
    def __init__(self, name, matType, standDim, usage, thermal,  dens, finish, con):```

grave jolt Oct 27, 2020, 2:12 AM

#

You can define a linked list of types, like Cons[int, Cons[str, Nil]] somehow, but that's pretty esoteric

...If you're doing that for the type checker, of course

gleaming rover Oct 27, 2020, 2:12 AM

#

You can define a linked list of types, like Cons[int, Cons[str, Nil]] somehow, but that's pretty esoteric
@grave jolt did someone say HList? 👋

halcyon trail Oct 27, 2020, 2:12 AM

#

but now I'm in a situation where I have some dataclass like this:

@dataclass
class foo:
    x: bar

And I want to upgrade it, backwards compatibility like this:

@dataclass
class foo:
    x: DefaultUnion[bar, baz]

raven ridge Oct 27, 2020, 2:12 AM

#

are you trying to do this for type checking, or for code generation?

halcyon trail Oct 27, 2020, 2:12 AM

#

both

#

well, not code generation

#

generic code

#

I'm not generating code

grave jolt Oct 27, 2020, 2:13 AM

#

@rotund yew You can use keyword args. Material(name="rock", matType="solid", ...). Also, check out PEP 8, Python's style guide -- names except class names are in snake_case.

halcyon trail Oct 27, 2020, 2:13 AM

#

Anyhow, from a type system perspective going from bar to Union[bar, baz] is backwards compatible for something that's an input

#

after all, you're broadening what you'll accept

#

however, because there will be no __type__ field in the existing json, it will not actually be backwards compatible

#

hence, I want this DefaultUnion thing. It type checks identical to Union

rotund yew Oct 27, 2020, 2:14 AM

#

@rotund yew You can use keyword args. Material(name="rock", matType="solid", ...). Also, check out PEP 8, Python's style guide -- names except class names are in snake_case.
@grave jolt Oh thank you!

grave jolt Oct 27, 2020, 2:14 AM

#

@rotund yew This is not really a help channel, so for further help see #❓｜how-to-get-help

halcyon trail Oct 27, 2020, 2:14 AM

#

but, my generic code is able to see that its' something different. And simply default the union type to the first type, if __type__ isnot supplied

rotund yew Oct 27, 2020, 2:15 AM

#

@rotund yew This is not really a help channel, so for further help see #❓｜how-to-get-help
@grave jolt Okay i'll check it, just joined the server yesterday

halcyon trail Oct 27, 2020, 2:15 AM

#

an alternative would be to change how I handle Union generally I suppose, but that seems dangerous, I'd rather error in general if __type__ isn't provided

#

I want to opt in

raven ridge Oct 27, 2020, 2:15 AM

#

so you're using __annotations__ dynamically at runtime to change the behavior of your code

halcyon trail Oct 27, 2020, 2:15 AM

#

Sure

gleaming rover Oct 27, 2020, 2:15 AM

#

hm this made me think of somethin

#

does anyone use lenses in Python?

halcyon trail Oct 27, 2020, 2:16 AM

#

not sure if you are implying with that statement that it is a form of code generation

#

@gleaming rover i guess like everything, somebody is using it, but lenses are typically used with immutable data structures, and python really makes it a pain to try to use immutable data structures throughout your code

#

I've played around with them in Kotlin

#

They're nice

gleaming rover Oct 27, 2020, 2:17 AM

#

I have a project where I more or less use namedtuple exclusively

#

just to see how it goes

halcyon trail Oct 27, 2020, 2:17 AM

#

heh, so youare thinking about what it will look like to change things when you have nested nametuples ?

raven ridge Oct 27, 2020, 2:17 AM

#

not sure if you are implying with that statement that it is a form of code generation
@halcyon trail Well, it's not, not exactly - but it's similar to @dataclass, in that you're using the annotations to do stuff, outside the normal type checking use case for annotations

gleaming rover Oct 27, 2020, 2:18 AM

#

oh man poor random user 😦

#

heh, so youare thinking about what it will look like to change things when you have nested nametuples ?
@halcyon trail yup

#

think I'll go hack something up

halcyon trail Oct 27, 2020, 2:18 AM

#

Eh, I dunno, dtaclass is a decorator, it actually does more or less generate code

raven ridge Oct 27, 2020, 2:18 AM

#

yeah, I blame discord for that.... heh

gleaming rover Oct 27, 2020, 2:18 AM

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too bored to work on startup

halcyon trail Oct 27, 2020, 2:18 AM

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my code is just a function

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it uses the fields function from datacalsses to inspect the types, and literally just branches based on that

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I'd call it introspection rather than generation.

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But yeah. Life is too short not to have generic, automated reflection 🙂

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(and thus, serialization/deserialization)

raven ridge Oct 27, 2020, 2:19 AM

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yeah. from my POV, that's still an esoteric thing to do with typing. Most users of type annotations use them only to with static type checkers.

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what you're doing doesn't sound unreasonable to me - at worst a little bit esoteric - but I have no idea how to accomplish it

halcyon trail Oct 27, 2020, 2:21 AM

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Esoteric in the context of pythons type system, or generally?

raven ridge Oct 27, 2020, 2:22 AM

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in the context of Python typing. It's generally used for opt-in static type checking.

halcyon trail Oct 27, 2020, 2:22 AM

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Sure

raven ridge Oct 27, 2020, 2:22 AM

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Union is implemented in Python - https://github.com/python/cpython/blob/3.9/Lib/typing.py#L388-L389 - so maybe it's possible to do what you're trying to do, if you dig into how typing works a bit.

halcyon trail Oct 27, 2020, 2:23 AM

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It's pretty.par for the course in most languages that have reflection and static typing

raven ridge Oct 27, 2020, 2:23 AM

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yes, but Python isn't really one of those, at least not IMHO.

halcyon trail Oct 27, 2020, 2:23 AM

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Oh it's definitely not statically typed

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But still, it's just an obvious use case

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How do you do deserialization otherwise?

raven ridge Oct 27, 2020, 2:24 AM

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In my experience it's pretty common to hit the limits of Python's type system and need to just throw up your hands and say Any. There are too many things that are reasonable uses of the language that are completely impossible to describe to type typing system.

gleaming rover Oct 27, 2020, 2:24 AM

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indeed.

halcyon trail Oct 27, 2020, 2:24 AM

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Yeah, no doubt

raven ridge Oct 27, 2020, 2:25 AM

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How do you do deserialization otherwise?
@halcyon trail the same as you're doing, but without the type hints.

halcyon trail Oct 27, 2020, 2:25 AM

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Static type annotations are an improvement but tbh I wish I was using a statically typed language often

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Err how?

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You have to tell it what to deserialize

raven ridge Oct 27, 2020, 2:26 AM

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you have a schema, the schema describes what types to expect on deserialization, you check the schema whenever you're pulling a field out to make sure that it conforms to the schema - but I wouldn't represent that schema using type hints, I'd represent it in some other form. jsonschema or xsd or protobuf or something.

halcyon trail Oct 27, 2020, 2:26 AM

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Sure

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Then in ninety nine percent of cases

raven ridge Oct 27, 2020, 2:27 AM

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I'd do it the same way as I would have done it before Python 3.5, before the language had type hints. 🤷

halcyon trail Oct 27, 2020, 2:27 AM

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You are repeateing yourself

raven ridge Oct 27, 2020, 2:27 AM

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not really - you're defining the schema in code. I would define the schema in another language entirely.

halcyon trail Oct 27, 2020, 2:27 AM

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But I already have the static types in python

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It's only not repetition if you aren't anyway using type annotations

raven ridge Oct 27, 2020, 2:28 AM

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right.

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and I wouldn't, heh

halcyon trail Oct 27, 2020, 2:28 AM

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Sure, that's different though

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But in this case,.you can see for the same amount of work, you get the additional benefits, mypy checking, IDE help, etc

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Schemas are ok if you need to exchange the data across languages

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This did give me an idea though, perhaps instead of stuffing it in the type I can put it somewhere else... Like the default value

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Or in the meta information for the field. We'll.see I guess

raven ridge Oct 27, 2020, 2:31 AM

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you get the additional benefits, mypy checking, IDE help, etc
IDEs often interpret type hints differently than mypy, and possibly incorrectly. And I generally find mypy more of a help than a hindrance.

halcyon trail Oct 27, 2020, 2:32 AM

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Not going to get into that one :-)

raven ridge Oct 27, 2020, 2:32 AM

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well, I'm just saying: you're taking it as a given that there's benefits to using typing for this. I disagree.

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I find mypy to be useful for the public interfaces of libraries, and that's pretty much it. Within a library, I find it much more of a hindrance than a help.

halcyon trail Oct 27, 2020, 2:34 AM

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Yes, I'm taking it as a given, for myself

raven ridge Oct 27, 2020, 2:39 AM

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I wonder if you can make DefaultUnion[Union[int, str, float]] work.

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that'd even allow you to make the default type explicit rather than implicit. UnionWithDefault[Union[int, str, float], str] or something.

halcyon trail Oct 27, 2020, 2:43 AM

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Well, I think I can make it work in terms of my deserialization code,.yes

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Making it type check,.not sure

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I can't inherit from Union I don't think

raven ridge Oct 27, 2020, 2:45 AM

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Making it type check,.not sure
I'd just use Any for that, heh.

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Though there may be a way to make it work. 🤷

halcyon trail Oct 27, 2020, 2:46 AM

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Yeah hopefully. Alternatively I could just not support a default, and programmatically rewrite all the current configs

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It's one or the other

lusty patrol Oct 27, 2020, 5:01 AM

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Hi all. Can anybody describe what I/O is and how it's used?

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Every definition I come across feels kind of arcane, other than using it as the definition for file objects (.py,.jpg,.exe, etc...). I ask because I feel like I'm missing a lot about I/O

smoky turret Oct 27, 2020, 5:06 AM

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in this context, IO refers to non-cpu bound operations that take a lot of CPU time to finish. Usually file operations, or socket stuff/requests

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or did you mean just general input/output user interaction stuff?

tired void Oct 27, 2020, 5:21 AM

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Hi can anyone suggest what is the best approach pandas or normal csv excel library

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if i want to fetch file data and import in db

haughty meadow Oct 27, 2020, 5:24 AM

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hey guys so i have a question i was recently looking up decorators and came across two ways to create a decorator, class decorator and function decorator. Trying to understand the difference i read that class decorators are better when you want to maintain the "state". I am not quite sure what they mean by this. Can someone help me with this

smoky turret Oct 27, 2020, 5:24 AM

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not "the state" but just maintaining state

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as in, theres some extra information your logic requires, that has to be persisted for some amount of time

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for example, if you had a decorator that implemented caching of the functions outputs, you have to maintain that cache (the state)

haughty meadow Oct 27, 2020, 5:27 AM

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ahh

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but wont the life scope of the function expire as soon as the callable is called in the class?

smoky turret Oct 27, 2020, 5:29 AM

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uhh, local function variables dissapear, yes, but the class attributes of the decorator wont, no

haughty meadow Oct 27, 2020, 5:30 AM

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alrighty i get it, thank you!

smoky turret Oct 27, 2020, 5:30 AM

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np

raven ridge Oct 27, 2020, 5:39 AM

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Hi all. Can anybody describe what I/O is and how it's used?
@lusty patrol I/O stands for "input and output", and it basically just means every place where your program needs to talk to something else before it can continue working - waiting for the filesystem to read a file off a disk, waiting for a web server to send an HTTP response, waiting for a database to give query results, waiting for the user to type or click something, etc. Any time your program needs to talk to any other program or device, basically. Any time input is taken into your program from some other place, or your program sends output to some other place.

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If data is being read into or written out of your Python program, that's I/O.

lusty patrol Oct 27, 2020, 7:09 AM

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That clears a lot up thanks very much for the explanation!

quick snow Oct 27, 2020, 8:59 AM

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I don't understand why after importing requests, I can use requests.adapters, even though it's not in the __init__.py of requests. Some kind of magic?

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I found some import magic in packages.py, but it seems to be unrelated.

gleaming rover Oct 27, 2020, 9:20 AM

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I don't understand why after importing requests, I can use requests.adapters, even though it's not in the __init__.py of requests. Some kind of magic?
@quick snow long story short, in __init__.py sessions is imported

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and in sessions something from adapters is imported.

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this resolves the adapters module in the requests package.

quick snow Oct 27, 2020, 11:07 AM

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Oh, interesting. I didn't know it worked that way

heady mauve Oct 27, 2020, 3:28 PM

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If one needs their code to run in a very tight, fast loop, would it be faster to check a condition once every loop and then change a few function definitions rather than check that condition every time you need to do something?

undone hare Oct 27, 2020, 3:36 PM

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Instead of changing function definitions, why don't you store the result of the condition as a variable, and use it everytime you need it?

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If your condition is O(1) though, the speed gain will be very little to be honest

heady mauve Oct 27, 2020, 4:03 PM

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okay. I guess it would be best to figure out how to use timeit and test this myself.

undone hare Oct 27, 2020, 4:28 PM

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The profiler would help here

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https://docs.python.org/3/library/profile.html

drifting slate Oct 27, 2020, 6:51 PM

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hi can i use python to send commands to the kernal

wicked holly Oct 27, 2020, 7:03 PM

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https://stackoverflow.com/questions/37032203/make-syscall-in-python @drifting slate

Stack Overflow

Make syscall in Python

I want to make syscall in Python and the function is not in libc, is there a way to do it in Python?

More specifically, I want to call getdents, whose manpage says
Note: There are no glibc wra...

charred wagon Oct 27, 2020, 8:32 PM

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This is not a help channel

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Please go to #❓｜how-to-get-help

swift imp Oct 27, 2020, 9:08 PM

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Say I have the triangle scenario, I make a new class C that inherits from both A and B. Both A and B have a foo property. How do I decide which foo to inherit in C? Well not decide but specify...

flat gazelle Oct 27, 2020, 9:11 PM

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python uses C3 linearization on its MRO, so it will take whichever is first in the bases list

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https://www.python.org/download/releases/2.3/mro/

Python.org

The Python 2.3 Method Resolution Order

The official home of the Python Programming Language

swift imp Oct 27, 2020, 9:18 PM

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ah, so I can't like

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ok, that makes sense

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Thanks

swift imp Oct 27, 2020, 9:47 PM

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Can you monkey patch a Dunder on a class? I can't imagine why you couldnt right?

charred wagon Oct 27, 2020, 9:49 PM

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Yes

swift imp Oct 27, 2020, 9:49 PM

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And yes I would want the monkey patch to affect all instances of the class

jade whale Oct 27, 2020, 10:15 PM

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Does anyone have a rec for a good technical write up on optimizing coroutines/generators/lazy code? I've been kicking around a personal project for a while and benchmarking lazily piped code has made me question some assumptions ive always made

raven ridge Oct 27, 2020, 11:10 PM

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Say I have the triangle scenario, I make a new class C that inherits from both A and B. Both A and B have a foo property. How do I decide which foo to inherit in C? Well not decide but specify...
@swift imp the one that gets used be default is the one that's earlier in the MRO (with just a diamond, that's the one you list first in your list of base classes). If you want the other one to get used, you can call it explicitly, using B.__getattr__(self, "foo") or the like

raven ridge Oct 27, 2020, 11:56 PM

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Or B.some_method(self) more commonly.

proud sandal Oct 28, 2020, 2:57 AM

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📎 unknown.png

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What does this mean ?

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@uncut sage

uncut sage Oct 28, 2020, 2:59 AM

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this doesn't belong here.

proud sandal Oct 28, 2020, 2:59 AM

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oh

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sorry

grave jolt Oct 28, 2020, 3:19 AM

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Why does Python allow both variants?

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!e

assert B"hi" == b"hi"
assert R"hi" == r"hi"
assert F"hi" == f"hi"

fallen slateBOT Oct 28, 2020, 3:19 AM

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@grave jolt :warning: Your eval job has completed with return code 0.

[No output]

grave jolt Oct 28, 2020, 3:20 AM

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I don't see a reason to have an uppercase variant.

reef otter Oct 28, 2020, 3:23 AM

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@grave jolt maybe for sql programmer 😂

peak spoke Oct 28, 2020, 3:29 AM

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I saw some cases where r and R were used to differentiate between regex and other uses, but I don't see a reason why not to allow it with other literals behaving in the same way

grave jolt Oct 28, 2020, 3:30 AM

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Hm, well, r vs R can indicate to a highlighting engine whether it's a regex or not.

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I see

raven ridge Oct 28, 2020, 3:34 AM

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https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals The grammar for that is pretty tortuous, heh

grave jolt Oct 28, 2020, 3:34 AM

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string literal go  br"rrr"

barren aurora Oct 28, 2020, 3:56 AM

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lol

prisma cypress Oct 28, 2020, 4:38 AM

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Hey guys what do you use for linting?

Because I'm coming across pycodestyle and pylint and aren't too sure the difference between the two.
I see some people using both as well.

main lynx Oct 28, 2020, 4:54 AM

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pycodestyle, it used to be called pep8 and afaik follows that doc

grave jolt Oct 28, 2020, 5:05 AM

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I recently started using flake8 because it's easy to configure and run, and I just wanted to stop the internal bikeshedding.

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ducky_bike

main lynx Oct 28, 2020, 5:17 AM

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that is basically pycodestyle

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but if it fixes bikeshedding, that is value

raven ridge Oct 28, 2020, 5:22 AM

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No, it's pycodestyle plus pyflakes plus any other plugins you choose to use, all integrated under a common configuration system, single CLI, and consistent pragmas to disable specific warnings

prisma cypress Oct 28, 2020, 6:10 AM

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Hello, question about project directory setup.

I'm running into issues regarding the way I set things up and would love some advice.

This is how I'm setting it up right now.

project/
│
├── .gitignore
├── spider/
│    ├── __init__.py
│    ├── spiderclass.py
│    └── spider_subclass.py
├── test/
│    └── test_spider.py
├── pipeline/
│    └── pipeline_script.py
├── LICENSE
├── README.md
└── requirements.txt

I'm running into importing troubles when importing the crawler class from test and pipeline folder.

hexed belfry Oct 28, 2020, 7:41 AM

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$excuse

#

All purpose excuse maker from Wimpy Kid

Subject

My Dog

Action

Injured

Obeject

My Lunch

Final Excuse

My Dog Injured My Lunch

mint forge Oct 28, 2020, 7:43 AM

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self botting?

teal yacht Oct 28, 2020, 7:43 AM

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showing off your self-bot, in a discussion channel, in a public server may not be the smartest move you've made

#internals-and-peps

...