wraith valve Oct 17, 2020, 6:45 PM

#

is that like image recognition or sth

bronze sail Oct 17, 2020, 6:45 PM

#

hmmm kinda, all with opencv and that center of mass only

wraith valve Oct 17, 2020, 6:46 PM

#

oh the white blocks are the ppl ic

bronze sail Oct 17, 2020, 6:46 PM

#

hah yes :d

molten shale Oct 17, 2020, 8:48 PM

#

what would be a good website/app for pc to represent a tree graph, specifically for data structure?

#

Like a tree version of this

#

https://visualgo.net/en/list?slide=1

VisuAlgo - Linked List (Single, Doubly), Stack, Queue, Deque

Linked List is a data structure consisting of a group of vertices (nodes) which together represent a sequence. Under the simplest form, each vertex is composed of a data and a reference (link) to the next vertex in the sequence. Try clicking Search(77) for a sample animation o...

bronze sail Oct 17, 2020, 10:45 PM

#

???

wraith valve Oct 17, 2020, 10:51 PM

#

like visually represent a graph?

#

i think any drawing tool should work

agile sundial Oct 17, 2020, 11:37 PM

#

i believe networkx can

bronze sail Oct 17, 2020, 11:39 PM

#

or graphviz

fiery cosmos Oct 18, 2020, 4:28 AM

#

hey so i was asking that i started with machine learning today from a youtuber named techwithtim i did the first one hour of his video and the thing was of linear regressions it \is kewl and interesting i had to download the data folder from a machine learning repository but one thing that ididnt understand was that how can put in my own values do i hv to modify the .csv file or what? and how does the computer get different values from the .csv? or it randomizes...ping if u answer me

#

Also can we make csv files with notepad and stuff?

#

@fiery cosmos if the data is small you can hardcode a csv fike else you need to write a program that writes to files. Now if you want to put your own values you indeed want to modify the csv file contents

#

also, next time look out for channel description, your question goes to #data-science-and-ml

#

hmmmmm

#

Ohhh

#

k

#

got it

#

can i make csv files with notepad

#

and

#

why does everyone's name has a substring "Gurkan"

#

uhh #ot0-psvm’s-eternal-disapproval

#

ask there

#

can i make csv files with notepad
@fiery cosmos yes

#

ook thanks

#

the gurkan question i just got curious cuz i saw many gurkan's nvm

limber zephyr Oct 18, 2020, 4:40 AM

#

I have a doubt

#

So I want to check if a phrase is profane

#

based on a list of profane words

#

like the function which checks it should return the probability of its profanity

#

if its definitely profane return 1

#

and if its somewhat porfane like 0.8

#

How can I go about this?

#

Can someone pls guide me

#

thanks!

fiery cosmos Oct 18, 2020, 4:42 AM

#

how do you define "somewhat profane"? What rule do you use?

limber zephyr Oct 18, 2020, 4:42 AM

#

I saw an example here

#

https://github.com/vzhou842/profanity-check/blob/master/profanity_check/profanity_check.py

GitHub

vzhou842/profanity-check

A fast, robust Python library to check for offensive language in strings. - vzhou842/profanity-check

#

vectorizer = joblib.load(pkg_resources.resource_filename('profanity_check', 'data/vectorizer.joblib'))
model = joblib.load(pkg_resources.resource_filename('profanity_check', 'data/model.joblib'))

def _get_profane_prob(prob):
  return prob[1]

def predict(texts):
  return model.predict(vectorizer.transform(texts))

def predict_prob(texts):
  return np.apply_along_axis(_get_profane_prob, 1, model.predict_proba(vectorizer.transform(texts)))```

#

the predict_prob function here retuns the same

fiery cosmos Oct 18, 2020, 4:42 AM

#

aha this is machine/deep learning

limber zephyr Oct 18, 2020, 4:43 AM

#

but uses a different wordlist

#

ohh

#

is there any other way

#

to go about this

#

instead of machine learning

#

I will learn it but not now

#

still in school xD

fiery cosmos Oct 18, 2020, 4:44 AM

#

well

📎 unknown.png

limber zephyr Oct 18, 2020, 4:44 AM

#

?

fiery cosmos Oct 18, 2020, 4:44 AM

#

you can see that comment it says sklearn

#

which is machine learning

limber zephyr Oct 18, 2020, 4:45 AM

#

okay

fiery cosmos Oct 18, 2020, 4:45 AM

#

and if you want another way all I see is do it from scratch(which is more pain)

limber zephyr Oct 18, 2020, 4:45 AM

#

I can do it

#

whats the other way

#

like how to best check for profanity

#

https://mystb.in/PointingModernTracy.python
This is my current profanity filter I made using regex. I want to make it more powerful though, by making the filter check for words like
if abc is a swear word the filter must detect aabc, abcc also as swear words

vernal venture Oct 18, 2020, 4:58 AM

#

@limber zephyr If you want a ratio of matching with a certain profane word, you could use any of the many classic string comparison algorithms such as Lavenstein distances.

limber zephyr Oct 18, 2020, 4:58 AM

#

whats that

#

sorry am new to this

#

can u pls explain

vernal venture Oct 18, 2020, 4:58 AM

#

https://www.google.com/search?q=lavenstein+distances&rlz=1C1CHBF_enUS913US913&oq=lavenstein+distances&aqs=chrome..69i57.2095j0j4&sourceid=chrome&ie=UTF-8

limber zephyr Oct 18, 2020, 4:59 AM

#

📎 unknown.png

#

How do I write this formula in python

#

bruh

#

are there libs for this

vernal venture Oct 18, 2020, 5:00 AM

#

https://stackabuse.com/levenshtein-distance-and-text-similarity-in-python/

Stack Abuse

Levenshtein Distance and Text Similarity in Python

Introduction
Writing text is a creative process that is based on thoughts and ideas which
come to our mind. The way that the text is written reflects our personality and
is also very much influenced by the mood we are in, the way we organize our
thoughts, the topic itself and ...

#

https://pypi.org/project/python-Levenshtein/

PyPI

python-Levenshtein

Python extension for computing string edit distances and similarities.

limber zephyr Oct 18, 2020, 5:03 AM

#

thanks a lot man

vernal venture Oct 18, 2020, 5:05 AM

#

If speed is a concern, there is a algorithm called 'Aho-Corasick' for pattern searching. There are derivatives of this that search for partial matches using that Lavenshtein algo

#

If you just want a quick and dirty solution, the python difflib lib has a sequence matcher thats easy to use.

#

https://stackoverflow.com/questions/10018679/python-find-closest-string-from-a-list-to-another-string/10018734 might be slow tho

Stack Overflow

Python: find closest string (from a list) to another string

Let's say I have a string "Hello" and a list

words = ['hello', 'Hallo', 'hi', 'house', 'key', 'screen', 'hallo','question', 'Hallo', 'format']
How can I find the n words that are the closest to "...

#

or https://pypi.org/project/profanity-check/

PyPI

profanity-check

A fast, robust library to check for offensive language in strings.

limber zephyr Oct 18, 2020, 5:53 AM

#

can I do py difflib.get_close_matches(list_of_words, possibilities_list) instead of py difflib.get_close_matches(word, possibilities_list)

#

@vernal venture

limber zephyr Oct 18, 2020, 6:22 AM

#

    def match(self, input_string, string_list):
        words = re.findall(r'\w+', input_string)
        return [word for word in words if word in string_list]

    def determine_profanity(self, phrase):
        # exact word-to-word check
        if self.match(phrase.lower(),self.get_grouped_profane_list()):
            return True
        if not self.smart_mode:
            return False
        # check for differences from profane words
        # if smart mode is enabled and the difference is reasonable, return true
        for unchecked_word in phrase.lower().split():
            close_prob_matches = difflib.get_close_matches(unchecked_word, self.get_grouped_profane_list(),
                                                           cutoff=0.75)
            if close_prob_matches:
                return True
        return False

    def is_profane(self, phrase):
        """Returns a boolean value,checking if the given phrase is profane or not"""
        if self.determine_profanity(phrase):
            return True
        return False


pf = ProfanityFilter(smart_mode=True)
print(pf.is_profane("luck hahhaha"))```

#

This is what I did

#

the profanity filter prints true for the word luck

#

I dont want this

#

however if abc is a cuss word and I type in abcc

#

then it works

#

how to fix this

#

please help

#

 def match(self, input_string, string_list):
        words = re.findall(r'\w+', input_string)
        word_list = []
        for word in words:
            if word in string_list:
                word_list.append(word)
        return word_list
        # need to check for continuous elements like if words[0] + words[1] together produce a profane word
        # upto three combinations```

#

Can someone pls guide me how to do this

#

the commented part

#

need to check for continuous elements like if words[0] + words[1] together produce a profane word
upto three combinations```

fiery cosmos Oct 18, 2020, 10:36 AM

#

WHAT S THE HARDEST ALGHORITHM

mint jewel Oct 18, 2020, 10:56 AM

#

given a brainfuck program, determine if it ever ends.

burnt hill Oct 18, 2020, 12:19 PM

#

hey guys

#

how does the hash() function work?

#

everytime i run it to a tuple it always produce a different output

mint jewel Oct 18, 2020, 12:39 PM

#

hash() calls __hash__ on its argument

fiery cosmos Oct 18, 2020, 1:08 PM

#

https://stackoverflow.com/questions/2070276/where-can-i-find-source-or-algorithm-of-pythons-hash-function

#

if you see this there is some math going on and it will return the result after the math

maiden kestrel Oct 18, 2020, 2:51 PM

#

bang bang bussi bang

humble jacinth Oct 18, 2020, 2:58 PM

#

If I put in a list from a previous function into another function as a parameter how do I make it work?

#

in a way that the second function edits the list

fiery cosmos Oct 18, 2020, 3:09 PM

#

can you paste your code?

#

@maiden kestrel pls don't do that in any channels

humble jacinth Oct 18, 2020, 3:09 PM

#

its pretty big lemme just give you the gist of it

fiery cosmos Oct 18, 2020, 3:10 PM

#

you can use !paste

#

!paste

halcyon plankBOT Oct 18, 2020, 3:10 PM

#

Pasting large amounts of code

If your code is too long to fit in a codeblock in discord, you can paste your code here:
https://paste.pydis.com/

After pasting your code, save it by clicking the floppy disk icon in the top right, or by typing ctrl + S. After doing that, the URL should change. Copy the URL and post it here so others can see it.

fiery cosmos Oct 18, 2020, 3:10 PM

#

and send the link

humble jacinth Oct 18, 2020, 3:11 PM

#

so basically I have two numbers in the list and I have to convert the integers into string using the second function

#

the list is made in the first function

#

problem is I keep getting the list as undefined

#

as a parameter that is

fiery cosmos Oct 18, 2020, 3:12 PM

#

hmm I can't help you without seeing the code

humble jacinth Oct 18, 2020, 3:12 PM

#

alright I'll post

fiery cosmos Oct 18, 2020, 3:12 PM

#

use this service its free

#

!paste

halcyon plankBOT Oct 18, 2020, 3:12 PM

#

Pasting large amounts of code

If your code is too long to fit in a codeblock in discord, you can paste your code here:
https://paste.pydis.com/

After pasting your code, save it by clicking the floppy disk icon in the top right, or by typing ctrl + S. After doing that, the URL should change. Copy the URL and post it here so others can see it.

humble jacinth Oct 18, 2020, 3:13 PM

#

https://paste.pythondiscord.com/ulekadireb.py

fiery cosmos Oct 18, 2020, 3:13 PM

#

okay I'll look into it

humble jacinth Oct 18, 2020, 3:13 PM

#

no problem

#

its not exactly complete

fiery cosmos Oct 18, 2020, 3:14 PM

#

def drawcards():
    import random
    Player1 = (random.randint(2, 14)), (random.randint(2, 14))
    Player2 = (random.randint(2, 14)), (random.randint(2, 14))
    if Player1[0] >= Player1[1]:
        return Player1[0], Player1[1]
    elif Player1[1] >= Player1[0]:
        return Player1[1], Player1[0]
    if Player2[0] >= Player2[1]:
        return Player2[0], Player2[1]
    elif Player2[1] >= Player2[0]:
        return Player2[1], Player2[0]
    return Player1
    return Player2
    card2str(Player1)

humble jacinth Oct 18, 2020, 3:14 PM

#

but you get the idea

fiery cosmos Oct 18, 2020, 3:14 PM

#

here you are returning from the function so card2str(player1) never gets called

humble jacinth Oct 18, 2020, 3:14 PM

#

so I have to place it outside?

#

or just place it at the very end

fiery cosmos Oct 18, 2020, 3:15 PM

#

why do you want to do that method inside that function (the logic is what I am asking)

humble jacinth Oct 18, 2020, 3:16 PM

#

so that I can assign the letters to when the integers are those values

#

I just want to pass on the values generated by Player1 my guy

#

the 2 values that is

#

keeps giving me undefined

fiery cosmos Oct 18, 2020, 3:18 PM

#

okay so these statements will never be executed

if Player2[0] >= Player2[1]:
        return Player2[0], Player2[1]
    elif Player2[1] >= Player2[0]:
        return Player2[1], Player2[0]
    return Player1
    return Player2
    card2str(Player1)

humble jacinth Oct 18, 2020, 3:18 PM

#

yeah for now

fiery cosmos Oct 18, 2020, 3:18 PM

#

No they will not in any case

humble jacinth Oct 18, 2020, 3:18 PM

#

for now im just focusing on player 1

#

oh the if statements

fiery cosmos Oct 18, 2020, 3:19 PM

#

since the first if - else block have return

humble jacinth Oct 18, 2020, 3:19 PM

#

alright lets say those are dealt with

#

I jsut want to know

#

OHHH

#

i get it now

#

I get what you mean

fiery cosmos Oct 18, 2020, 3:20 PM

#

also player one is a tuple not a list

humble jacinth Oct 18, 2020, 3:20 PM

#

so I can just return at the end

fiery cosmos Oct 18, 2020, 3:20 PM

#

yes

humble jacinth Oct 18, 2020, 3:20 PM

#

I'll just switch those positions

#

0 = 1

#

somethin like that

#

then maybe it'll work I guess

#

thanks

#

I just want to make sure the values are descending for the list

fiery cosmos Oct 18, 2020, 3:21 PM

#

also next time check the channel descriptions, if you want to get help with algorithms and data-structures then this is the perfect place, else if you have problems with python implementations be sure to check out #❓｜how-to-get-help

humble jacinth Oct 18, 2020, 3:22 PM

#

alright

#

got you

unborn wharf Oct 18, 2020, 3:38 PM

#

yeah

boreal linden Oct 18, 2020, 7:18 PM

#

I give up, anyone have any clue how to solve?

📎 unknown.png

#

deadline in 40 minutes, spending ages on it.

#

Or a tip/general direction to take a look at would also be great.

stable pecan Oct 18, 2020, 7:19 PM

#

what's the answer to the hint?

boreal linden Oct 18, 2020, 7:20 PM

#

it would seem to me that an internal node cannot have more than 4 edges

stable pecan Oct 18, 2020, 7:20 PM

#

that's right

boreal linden Oct 18, 2020, 7:20 PM

#

I don't understand how that helps me.

#

I'm trying to topologically bound it, and algebraically, but cannot find a way either way

#

even still, consider a tree with 5 nodes. One in the middle, and 4 leaves

#

this has 4 leaves, and 5 nodes. This exceeds the supposed upper bound?

#

nevermind, I'm no longer thinking straight.

stable pecan Oct 18, 2020, 7:24 PM

#

that's the closest you can get to the bound

#

it's exactly the bound

#

well, i guess all the:

   o  o
   |  |
o--o--o--o
   |  |
   o  o

#

type graphs also hit the bound

wraith valve Oct 18, 2020, 7:27 PM

#

well i think u can try out max leaves are in a tri-ary tree

boreal linden Oct 18, 2020, 7:30 PM

#

Right, I understand. Let me try to formulate a formal proof for it, thank you 🙂

wraith valve Oct 18, 2020, 7:33 PM

#

u only need to show it works for trees with 3 branches

#

cuz trees with 2 1 or 0 are bounded by the 3 branches

#

ofc if they have the same height

fiery cosmos Oct 18, 2020, 7:37 PM

#

I think you can use mathematical induction?

wraith valve Oct 18, 2020, 7:37 PM

#

not sure what other way u can go about this

fiery cosmos Oct 18, 2020, 7:38 PM

#

yeah I always try mathematical induction first to prove something xD

wraith valve Oct 18, 2020, 7:38 PM

#

well usually with these types of problems induction is the way to go

boreal linden Oct 18, 2020, 7:47 PM

#

I really need to hurry to solve it, so I kind-of-messily did it as such

#

📎 unknown.png

#

not too pretty, but hopefully enough 😉

wraith valve Oct 18, 2020, 7:50 PM

#

dont know if thats formal tho

boreal linden Oct 18, 2020, 7:50 PM

#

It is definitely not.

wraith valve Oct 18, 2020, 7:52 PM

#

idk if thats even a proof

#

it sounds like an intuitive explaination of some sort

boreal linden Oct 18, 2020, 7:53 PM

#

Yeah, I should use a formal proof structure

#

I should probably use case distinction with induction

#

But I need to do 2 more exercises within 7 minutes.

wraith valve Oct 18, 2020, 7:54 PM

#

bro...

eager hamlet Oct 18, 2020, 8:32 PM

#

gamer

real coral Oct 19, 2020, 12:56 AM

#

In the game “Battleships”, each player has an 8x8 grid, on which they place 5 ships of varying lengths. The players take turns firing shots at the other player’s grid by giving (X, Y) coordinates.

If the (X, Y) coordinate given contains part of an enemy ship, that portion of the ship is destroyed, and the opposing player announces a “hit”. Once all portions of a ship are hit, that ship is “sunk”. A player wins once they sink all of their opponent’s ships.

Consider the following points:
· How could you represent the 8x8 grid? If there are multiple options, what are the pros and cons of each?

#

For the above question

#

I am not sure on what the appropriate data sturcture to use when storing the board

agile sundial Oct 19, 2020, 12:57 AM

#

2d list?

real coral Oct 19, 2020, 12:58 AM

#

But why @agile sundial

#

And by 2d u mean

#

[0,0,0,0
0,0,0,0,
0,0,0,0]

#

For example

#

Or?

agile sundial Oct 19, 2020, 12:59 AM

#

that's a 1d list still

#

a 2d list has lists in it

real coral Oct 19, 2020, 12:59 AM

#

So

#

[[0,0,0,0,0]
[0,0,0,0,0]]

agile sundial Oct 19, 2020, 1:00 AM

#

the lists still have to be separated by commas

real coral Oct 19, 2020, 1:00 AM

#

Yes ofc

#

Just is that what u meant

agile sundial Oct 19, 2020, 1:00 AM

#

yeah

real coral Oct 19, 2020, 1:01 AM

#

Why is that the best tho?

agile sundial Oct 19, 2020, 1:01 AM

#

idk if it is, it's just the first one that came to mind

real coral Oct 19, 2020, 1:01 AM

#

Fair enough

#

Thanks

flat sorrel Oct 19, 2020, 1:05 AM

#

It depends on what information you want to store on the board

#

and how you're going to use it

limber zephyr Oct 19, 2020, 4:12 AM

#

 def match(self, input_string, string_list):
        words = re.findall(r'\w+', input_string)
        word_list = []
        for word in words:
            if word in string_list:
                word_list.append(word)
        return word_list
        # need to check for continuous elements like if words[0] + words[1] together produce a profane word
        # upto three combinations```

@limber zephyr

#

can someone pls help me with this?

wraith valve Oct 19, 2020, 5:09 AM

#

like in what whay

#

in what it does

torn epoch Oct 19, 2020, 5:13 AM

#

Hi

limber zephyr Oct 19, 2020, 5:57 AM

#

#help-popcorn

#

pls help me

vernal venture Oct 19, 2020, 6:13 AM

#

@limber zephyr What is your question

limber zephyr Oct 19, 2020, 6:14 AM

#

#help-popcorn

#

@vernal venture

#

thnks!

real coral Oct 19, 2020, 7:24 AM

#

I am not sure tho @flat sorrel

flat sorrel Oct 19, 2020, 7:25 AM

#

then start with the generic 2d array

real coral Oct 19, 2020, 7:25 AM

#

Ok thanks @flat sorrel

elfin storm Oct 19, 2020, 10:42 AM

#

im having issues with storing and returning the value of the removed node. help ples.

📎 codehelppls.PNG

flat sorrel Oct 19, 2020, 10:46 AM

#

You're returning the node itself, not the value stored in the node

elfin storm Oct 19, 2020, 10:46 AM

#

how would i retrieve the value inside of the node then? @flat sorrel

fiery cosmos Oct 19, 2020, 10:53 AM

#

guys tensor flow has been compiling for forever can someone pls tell me whats happening

📎 Screenshot_20201019_064803.png

#

i was tryna get bazel idk how all this happend

#

should i end the compile?

oblique panther Oct 19, 2020, 2:09 PM

#

@fiery cosmos are you pip installing it or are you actually compiling from source?

#

@elfin storm your nodes should have an attribute named "value" or something like that

#

also I see that you're using two leading underscores to indicate a private value; one underscore is preferred

fiery cosmos Oct 19, 2020, 2:11 PM

#

what is a good resource for learning data structures and algorithems for free?

agile sundial Oct 19, 2020, 2:11 PM

#

clrs

#

you can find it online for fre

fiery cosmos Oct 19, 2020, 2:12 PM

#

is it a course?

agile sundial Oct 19, 2020, 2:12 PM

#

it's a textbook

oblique panther Oct 19, 2020, 2:13 PM

#

books

fiery cosmos Oct 19, 2020, 2:13 PM

#

where can i find it for free?

#

nvm ill just google that

#

thanks for the help

agile sundial Oct 19, 2020, 2:13 PM

#

there's pdfs floating around

fiery cosmos Oct 19, 2020, 2:13 PM

#

its on python right?

oblique panther Oct 19, 2020, 2:14 PM

#

algorithms and data structures don't care what language you implement them in

agile sundial Oct 19, 2020, 2:14 PM

#

it's in pseudocode

oblique panther Oct 19, 2020, 2:14 PM

#

yeah, A&D textbooks usually use pseudocode

agile sundial Oct 19, 2020, 2:14 PM

#

which you should be able to translate into python, given a decent understanding of python syntax

oblique panther Oct 19, 2020, 2:14 PM

#

if you translate that pseudocode into python it should be really helpful for you

#

ayyy by the mouth of two

agile sundial Oct 19, 2020, 2:15 PM

#

pog

fiery cosmos Oct 19, 2020, 2:15 PM

#

oh lol, thank you so much

#

this is the one right? [https://github.com/CodeClub-JU/Introduction-to-Algorithms-CLRS]

agile sundial Oct 19, 2020, 2:17 PM

#

looks like it

fiery cosmos Oct 19, 2020, 3:04 PM

#

The almighty clrs

fiery cosmos Oct 19, 2020, 3:43 PM

#

á

normal plaza Oct 19, 2020, 5:02 PM

#

wasn't sure where to post, i'm new here 😅

#

does anyone here know how to solve this?

west surge Oct 19, 2020, 5:06 PM

#

What does that have to do with python

normal plaza Oct 19, 2020, 5:06 PM

#

wait

#

hold on

#

ohhh shitttt dude i thought python was just the name of the discord

#

didnt realize it was for the program lmfao my bad boys

agile sundial Oct 19, 2020, 5:13 PM

#

it is a programming language

quasi hatch Oct 19, 2020, 5:34 PM

#

wait what did he post lol

west surge Oct 19, 2020, 6:49 PM

#

His classwork

viscid kernel Oct 19, 2020, 6:52 PM

#

hey friends, im wanting to verify the sizes of messages im sending in json through kafka, is there a built in function to see the size of something? i know of sys.issizeof() but from my understanding thats telling me the size in memory

#

more or less need it to write a test as my messages will get rejected if they > 1MB

#

i could be misunderstanding the concept a little..

snow swift Oct 19, 2020, 7:15 PM

#

wrong channel

#

@viscid kernel

viscid kernel Oct 19, 2020, 7:15 PM

#

which would be correct? sorry

#

figured it was a data structure question 🙂

fiery cosmos Oct 19, 2020, 9:50 PM

#

ghost ping?

fiery cosmos Oct 19, 2020, 11:01 PM

#

hey guys new here need some help with using how ti find gcd - Euclid’s algorithm - in python

brave oak Oct 20, 2020, 1:48 AM

#

hey friends, im wanting to verify the sizes of messages im sending in json through kafka, is there a built in function to see the size of something? i know of sys.issizeof() but from my understanding thats telling me the size in memory
@viscid kernel ...the size of the JSON?

#

len?

viscid kernel Oct 20, 2020, 2:04 AM

#

@brave oak no in bytes

brave oak Oct 20, 2020, 2:21 AM

#

@brave oak no in bytes
@viscid kernel but why?

#

like you mean a JSON format string, right?

viscid kernel Oct 20, 2020, 2:41 AM

#

yes, im shipping it elsewhere via kafka

viscid kernel Oct 20, 2020, 3:55 AM

#

but yeah in json

brave oak Oct 20, 2020, 5:55 AM

#

but yeah in json
@viscid kernel yeah then that's the length of the JSON string

#

the size of the object would be the amount of memory the Python object wrapping the data in question takes, not the size of the data itself when serialised and transmitted

fiery cosmos Oct 20, 2020, 6:53 AM

#

@fiery cosmos It's actually quite simple

def gcd(a, b):
  if not a:
    return b
  return gcd(b % a, a)

limber zephyr Oct 20, 2020, 7:11 AM

#

someone pls help me

#

I need list matching

#

or matching each word of a sentence with a list

#

it should also be fast

#

fuzz didnt work

#

I explained why there

#

pls help me

#

thanks!

#

#help-pie

quartz oxide Oct 20, 2020, 10:24 AM

#

def concat(queue) :
    l = []
    while not queue.is_empty() :
        l.append(queue.pop())
        
    for i in range(len(l)) :
        l[i] += l[i+1]
        
    return l

#

The goal is to concatenate elements of a queue

#

like it has to pass these tests

#

>>> queue = Queue()
>>> queue.push('ab')
>>> queue.push('cd')
>>> concat()
'abcd'
>>> queue.is_empty()
True

#

Anyone help ?

agile sundial Oct 20, 2020, 10:33 AM

#

your code will add together the zeroth element and the first element, then on the next iteration it will add together the first and the second, then on the next it will add the second and the third

stable pecan Oct 20, 2020, 10:38 AM

#

are you trying to implement it as a doubly-linked list like a deque

quartz oxide Oct 20, 2020, 10:38 AM

#

Yes its kinda like that

#

But i cant use the function deque

stable pecan Oct 20, 2020, 10:39 AM

#

I usually make a "Block" class first then build the deque from blocks

quartz oxide Oct 20, 2020, 10:39 AM

#

Good idea I'll try it

#

@agile sundial I think thats goal lol cuz the elements of the queue are strings

agile sundial Oct 20, 2020, 10:41 AM

#

sure, but try it

quartz oxide Oct 20, 2020, 10:41 AM

#

oh sorry , you're right it gives me : 'ab, abcd'

stable pecan Oct 20, 2020, 10:42 AM

#

you could just be cheeky and use a string buffer

quartz oxide Oct 20, 2020, 10:42 AM

#

I wont need a list I think ? @stable pecan

stable pecan Oct 20, 2020, 10:42 AM

#

no

quartz oxide Oct 20, 2020, 10:43 AM

#

Okay

stable pecan Oct 20, 2020, 10:44 AM

#

this is what i meant with the buffer:

In [16]: from io import StringIO

In [17]: queue = StringIO()

In [18]: queue.write('ab')
Out[18]: 2

In [19]: queue.write('cd')
Out[19]: 2

In [20]: queue.getvalue()
Out[20]: 'abcd'

probably not what they want from you though

quartz oxide Oct 20, 2020, 10:45 AM

#

Ohh i know but like you said its not acceptable

#

Normally its not that hard i just need to think easy

#

its not that complicated

stable pecan Oct 20, 2020, 10:46 AM

#

i mean you could implement it with a list -- and it's not even inefficient if you're join ing the list afterwards, but i don't know what exactly they intend for you

#

put if you're suppose to be popping the 0th element off, then maybe they want a deque data structure

quartz oxide Oct 20, 2020, 10:47 AM

#

Ohhhhh thats it

#

wait

#

I used the keyword : join

#

like :

#

return ''.join(queue)

#

It works

#

Thank u @stable pecan

stable pecan Oct 20, 2020, 10:54 AM

#

np

agile sundial Oct 20, 2020, 12:21 PM

#

what's the problem?

junior ether Oct 20, 2020, 12:36 PM

#

Hello, my program below display an encryption grid but is it optimized?

#

def grille():
    alphabet = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
                'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
    print("    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z")
    print("-" * 55)
    y = 1
    i = 0
    for x in alphabet:
        deb = alphabet.index(x)
        if i == 0:
            print(x + " | " + " ".join(alphabet[deb:26]))
            i = i + 1
        else:
            print(x + " | " + " ".join(alphabet[deb:26]) + " " + " ".join(alphabet[0:y]))
            y = y+ 1


grille()```

flat sorrel Oct 20, 2020, 1:12 PM

#

!code

halcyon plankBOT Oct 20, 2020, 1:12 PM

#

Discord has support for Markdown, which allows you to post code with full syntax highlighting. Please use these whenever you paste code, as this helps improve the legibility and makes it easier for us to help you.

To do this, use the following method:

```python
print('Hello world!')
```

Note:
• These are backticks, not quotes. Backticks can usually be found on the tilde key.
• You can also use py as the language instead of python
• The language must be on the first line next to the backticks with no space between them

This will result in the following:

print('Hello world!')

flat sorrel Oct 20, 2020, 1:14 PM

#

but anyways, you can use enumerate to get the index of the element while looping through alphabet. That way you don't have to waste time searching for the index of each element

#

the usage of i and y is redundant if you follow my above suggestion

viscid kernel Oct 20, 2020, 1:22 PM

#

the size of the object would be the amount of memory the Python object wrapping the data in question takes, not the size of the data itself when serialised and transmitted
@brave oak right gotcha, i guess im wondering if theres a way to gauge the latter

brave oak Oct 20, 2020, 1:23 PM

#

@brave oak right gotcha, i guess im wondering if theres a way to gauge the latter
@viscid kernel yeah, so that's just the length of the string in JSON format, right

viscid kernel Oct 20, 2020, 1:25 PM

#

@brave oak ah ok, apologize my nativity, didnt realize that would correlate to bytes

junior ether Oct 20, 2020, 1:35 PM

#

@flat sorrel Ok , I don't often use enumerate, thank you !

flat sorrel Oct 20, 2020, 2:22 PM

#

np

chilly valve Oct 20, 2020, 7:24 PM

#

Technically, The length of a string doesn't nessacerily corelate to bytes, it corelates to characters, which can be 8, 16 or 32 bits long, depending uuencode details. JSON only specifies that certain characters need to be escaped, so you may want: convert to string; convert to bytes; take length. For an int that would be len(str(value).encode()) I'm not sure what it will be for your JSON library.

flat pier Oct 20, 2020, 7:27 PM

#

(unicode, not uuencode — the latter is an old email helper tool)

viscid kernel Oct 20, 2020, 7:46 PM

#

Technically, The length of a string doesn't nessacerily corelate to bytes, it corelates to characters, which can be 8, 16 or 32 bits long, depending uuencode details. JSON only specifies that certain characters need to be escaped, so you may want: convert to string; convert to bytes; take length. For an int that would be len(str(value).encode()) I'm not sure what it will be for your JSON library.
@chilly valve thanks, this makes sense

lusty sand Oct 20, 2020, 8:03 PM

#

Could someone assist me with singly linked lists? I need help with adding nodes in between the linked list

agile sundial Oct 20, 2020, 8:04 PM

#

do you mean inserting a node?

lusty sand Oct 20, 2020, 8:04 PM

#

correct

#

not at the beginning or the end

agile sundial Oct 20, 2020, 8:04 PM

#

what are you having trouble with?

lusty sand Oct 20, 2020, 8:04 PM

#

Creating an insertAfter function

#

insertAfter takes two parameters, an integer index (0 and higher) and a string value, creates a new node object
with the string value as the new node’s element, and inserts that node object after the ith element of the SLL. For
the purpose of this method the items of the SLL are numbered starting with 1, not 0. If the value of the index is
greater than the number of items in the SLL the new node is to be inserted after the last item (after the rear or tail)
and becomes the new rear or tail.

agile sundial Oct 20, 2020, 8:06 PM

#

have you tried anything?

lusty sand Oct 20, 2020, 8:09 PM

#

  """LIFO Stack implementation using a singly linked list for storage."""

 #-------------------------- nested _Node class --------------------------
  class _Node:         # "inner" class
    """Lightweight, nonpublic class for storing a singly linked node."""
    __slots__ = '_element', '_next'           # streamline memory usage

    def __init__(self, element, next):        # initialize node's fields
        self._element = element               # reference to user's element
        self._next = next                     # reference to next node

    def setNext(self, next):
        self._next = next
    
    def getNext(self):
        return self._next
  
    def setElement(self, element):
        self.element = _element
    
    def getElement(self):
        return self._element
        
  #------------------------------- stack methods -------------------------------
  def __init__(self, head = None, size = 0):
    """Create an empty list."""
    self._head = head                       # reference to the head node
    self._size = size                       # number of stack elements

  def getSize(self):
    """Return the number of elements in the list."""
    return self._size

  def isEmpty(self):
    """Return True if the list is empty."""
    return self._size == 0

  def add (self, element):
    """Add element element to the end of the list."""
    node = self._Node(element, None)
    if self.isEmpty():
        self._head = node
    else:
        cursor = self._head
        while cursor.getNext() is not None:
            cursor = cursor.getNext( )
        cursor.setNext(node)
    print('Adding # ', self._size, ' element: ', node.getElement())
    self._size += 1```

#

this was given by the professor

agile sundial Oct 20, 2020, 8:09 PM

#

and your attempt at the insertAfter function?

lusty sand Oct 20, 2020, 8:09 PM

#

    """Insert an element after the ith element of the list."""
    
    node = self._Node(element, None)
    
    currentNode = self._head
    
    #If the list is empty, then node wil be inserted at the head
    if self.isEmpty():
        self._head = node
    
    #Detemine if i is greater than the size of Singly Linked List
    if i > self.getSize():
        self.add(element)
    
    #insert in the interior
    counter = 0 
    while True:
        if counter == i:
            prevNode._next = element
            element._next = currentNode
            break
        prevNode = currentNode
        currentNode = currentNode._next
        counter += ```

#

and the cases for the specific function

#

Cases: (1) insert into empty list, (2) insert before the head, (3) insert in the interior

agile sundial Oct 20, 2020, 8:15 PM

#

what doesn't work

olive vine Oct 20, 2020, 8:20 PM

#

hey @lusty sand and I are working on this together. We are having issues trying to get and set the next value. He keeps getting an error that says something along the lines of "_next dosn't allow str values"

#

I think we are just stuck trying to call and assign the values because the nested class and variables are private

vocal gorge Oct 20, 2020, 8:27 PM

#

can you provide, like, the actual traceback?

olive vine Oct 20, 2020, 8:29 PM

#

hold on, he is running his code rn

lusty sand Oct 20, 2020, 8:29 PM

#

AttributeError Traceback (most recent call last)
<ipython-input-4-de4afb125b4a> in <module>
8 SLL.remove()
9 elif a[0] == "IA":
---> 10 SLL.insertAfter(int(a[1]), a[2])
11 else:
12 pass

<ipython-input-1-c99b8eff9a2f> in insertAfter(self, i, element)
102 if counter == i:
103 prevNode._next = element
--> 104 element._next = currentNode
105 break
106 prevNode = currentNode

AttributeError: 'str' object has no attribute '_next'

olive vine Oct 20, 2020, 8:29 PM

#

thank you both for helping! 🙂

vocal gorge Oct 20, 2020, 8:30 PM

#

well, element is a string, apparently.

#

if you're inserting into a linked list, you probably forgot to wrap the "element" (the element's value, really) into a Node

olive vine Oct 20, 2020, 8:31 PM

#

how do you do that?

agile sundial Oct 20, 2020, 8:31 PM

#

you need to create a node with the string as a value

olive vine Oct 20, 2020, 8:34 PM

#

would either one you be available to join a voice channel w us?

agile sundial Oct 20, 2020, 8:34 PM

#

I cannot

olive vine Oct 20, 2020, 8:35 PM

#

these are the samples we have been trying to work off of: https://stonesoupprogramming.com/2017/05/19/singly-linked-list-python/ https://stackoverflow.com/questions/41646430/inserting-node-at-a-specific-location-python https://stackoverflow.com/questions/46350266/insert-a-node-at-nth-position-in-linked-list-in-python

Stone Soup Programming

archer920gmailcom

Singly Linked List—Python

Many of my programming students get asked to implement Linked Lists as a way to learn about data structures in programming. Now I am going to be very honest about this topic when it comes to Python…

Stack Overflow

Inserting Node at a specific location python

This question is a hackerrank challenge. link here: https://www.hackerrank.com/challenges/insert-a-node-at-a-specific-position-in-a-linked-list

"""
Insert Node at a specific position in a linked l...

Stack Overflow

insert a node at Nth position in linked list in python

I am trying to insert a node "item" in position "index" in a linked list, I have the following code and to me it sounds fine, but it is not working right.

I would really appreciate if someone can ...

#

do any of them show the wrapping of the element?

desert cedar Oct 20, 2020, 8:38 PM

#

Yes,

Temp = Node(item)``` in that last link.

olive vine Oct 20, 2020, 8:41 PM

#

is that different than node = self._Node(element, None)

#

?

flat pier Oct 20, 2020, 8:41 PM

#

oh it’s a little weird that the Node class is inside the List class

lusty sand Oct 20, 2020, 8:42 PM

#

  class _Node:         # "inner" class
    """Lightweight, nonpublic class for storing a singly linked node."""
    __slots__ = '_element', '_next'           # streamline memory usage

    def __init__(self, element, next):        # initialize node's fields
        self._element = element               # reference to user's element
        self._next = next                     # reference to next node```

#

exactly!

olive vine Oct 20, 2020, 8:42 PM

#

lol yeah, i think that is what is throwing us off

tardy rose Oct 20, 2020, 8:44 PM

#

I think self.next should be another instance pointer of the class, as in C

flat pier Oct 20, 2020, 8:45 PM

#

what would that mean in Python terms?

tardy rose Oct 20, 2020, 8:47 PM

#

self.next = *_Node(some_element,None)```

#

If I didnt get anything mixed up

desert cedar Oct 20, 2020, 8:48 PM

#

We dont' have a pointer class in python, you'd put the regular object there.

#

* is the operator for unpacking

olive vine Oct 20, 2020, 8:49 PM

#

self.next is actually self._next... are we allowed to switch it from private to public for this method?

vocal gorge Oct 20, 2020, 8:50 PM

#

@tardy rose in Python, things aren't really copied ever without you explicitly asking for that. Everything is a "pointer" in a way.

desert cedar Oct 20, 2020, 8:50 PM

#

There is no private in python, but _ is used to tell other developers to treat it as if it's private

tardy rose Oct 20, 2020, 8:50 PM

#

U do have a pointer class in Python as u can do **args and other things

agile sundial Oct 20, 2020, 8:50 PM

#

uh that's not a pointer

mint jewel Oct 20, 2020, 8:50 PM

#

that is not a pointer

tardy rose Oct 20, 2020, 8:50 PM

#

Why not?

vocal gorge Oct 20, 2020, 8:51 PM

#

just because something uses an asterisk in one language doesn't mean all occurences of * in other languages mean the same thing 😉

mint jewel Oct 20, 2020, 8:51 PM

#

the C equivalent would be ...

agile sundial Oct 20, 2020, 8:51 PM

#

what. it's just not a pointer

vocal gorge Oct 20, 2020, 8:51 PM

#

* and ** in python have no relation to dereferencing, as simple as that

desert cedar Oct 20, 2020, 8:51 PM

#

prevNode._next = element
This line seems like a problem, you are using element here, which is the string value, and not the node you made.

olive vine Oct 20, 2020, 8:54 PM

#

so how do we access the next element? When we try to call the getNext() and setNext() methods?

#

this is what is have rn def insertAfter (self, i, element): """Insert an element after the ith element of the list.""" node = self._Node(element, None) #-------my code starts here------ cursor = self._head if self.isEmpty() or i == 0: self._head = node elif i >= self.getSize(): self.add(element) else: cur = self._head count = 0 while count < (i-1): cur = cur.getNext() count += 1 next = cur.getNext() cur.setNext = node

tardy rose Oct 20, 2020, 8:54 PM

#

in Python is not as the same in C, but it can be used in number of places to store more info then "u can"
as such

>>> mylist = [1, 2, 3, 4, 5]
>>> mylist
[1, 2, 3, 4, 5]
>>> start, *list_, final = mylist
>>> start
1
>>> list_
[2, 3, 4]
>>> final
5
>>> start1, list_1, final1 = mylist
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: too many values to unpack (expected 3)
>>>```

olive vine Oct 20, 2020, 8:54 PM

#

this is the error i'm getting ```AttributeError Traceback (most recent call last)
<ipython-input-57-d5bf88704ca6> in <module>
51 SLL1.remove()
52 elif a[0] == "IA":
---> 53 SLL1.insertAfter(int(a[1]), a[2])
54 else:
55 pass

<ipython-input-56-d6764c06cf5b> in insertAfter(self, i, element)
98 count += 1
99 next = cur.getNext()
--> 100 cur.setNext = node
101
102

AttributeError: '_Node' object attribute 'setNext' is read-only```

tardy rose Oct 20, 2020, 8:55 PM

#

U r trying to put data into an method, as what I can see

#

On the last line

desert cedar Oct 20, 2020, 8:58 PM

#

You are trying to reassign the setNext method to be the node, instead of calling the setNext method with the node

tardy rose Oct 20, 2020, 8:58 PM

#

^
Better explanation then mine

vocal gorge Oct 20, 2020, 9:00 PM

#

@tardy rose

in Python is not as the same in C, but it can be used in number of places to store more info then "u can"
as such
How's that related to pointers?

tardy rose Oct 20, 2020, 9:01 PM

#

Well it is what pointers do, and I have just realised I was only talking about dynamic lists in c as pointers and not the entire subjects, apologies

vocal gorge Oct 20, 2020, 9:06 PM

#

...are you thinking about vectors, perhaps?

agile sundial Oct 20, 2020, 9:07 PM

#

probably, yeah

tardy rose Oct 20, 2020, 9:07 PM

#

I dont think its vectors tbh

#

Maybe the term in my place is a bit different

agile sundial Oct 20, 2020, 9:08 PM

#

i think it's the same everywhere

chilly valve Oct 20, 2020, 9:08 PM

#

vectors usually means an array of pointers.

tardy rose Oct 20, 2020, 9:10 PM

#

Ok, well I am just used to calling them 2d pointer arrays, thats what I learned...

vocal gorge Oct 20, 2020, 9:10 PM

#

yeah, a vector is a contigious dynamic array, basically https://en.cppreference.com/w/cpp/container/vector

agile sundial Oct 20, 2020, 9:11 PM

#

analogous to python's lists

tardy rose Oct 20, 2020, 9:11 PM

#

Is this inbuilt feature in C++?

vocal gorge Oct 20, 2020, 9:11 PM

#

yup, Python lists are secretly Vectors of pointers to PyObjects

tardy rose Oct 20, 2020, 9:12 PM

#

Bcus in C I had to create and manage it all by myself

vocal gorge Oct 20, 2020, 9:12 PM

#

Is this inbuilt feature in C++?
well, yes, it's in the standard library
Bcus in C I had to create and manage it all by myself
yeah, in C you don't get builtin vectors

tardy rose Oct 20, 2020, 9:12 PM

#

I think that was why I am unfamilier with that term

olive vine Oct 20, 2020, 9:20 PM

#

okay, thank you guys for trying to help. Really appreciate it!

lusty sand Oct 20, 2020, 9:38 PM

#

I'm still struggling

flat pier Oct 20, 2020, 9:38 PM

#

with what error?

lusty sand Oct 20, 2020, 9:39 PM

#

so i'm using this guys code as a reference

#

📎 unknown.png

#

its from a youtube

#

https://www.youtube.com/watch?v=Z0uqXuzCQTo&list=PLzjoZGHG3J8vdUH75YPqmO7lbQl_M-xXo&index=6&ab_channel=TheProgrammerinYou

YouTube

The Programmer in You

Singly Linked List in Python (Part 6/10) - Python implementation of...

In this lecture, you learn the Python implementation of new node insertion in between two other nodes of a Singly Linked List

▶ Play video

flat pier Oct 20, 2020, 9:42 PM

#

okay, and what is your problem?

lusty sand Oct 20, 2020, 9:42 PM

#


---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-de4afb125b4a> in <module>
      8         SLL.remove()
      9     elif a[0] == "IA":
---> 10         SLL.insertAfter(int(a[1]), a[2])
     11     else:
     12         pass

<ipython-input-1-c99b8eff9a2f> in insertAfter(self, i, element)
    102         if counter == i:
    103             prevNode._next = element
--> 104             element._next = currentNode
    105             break
    106         prevNode = currentNode

AttributeError: 'str' object has no attribute '_next'

#

its the same one

#

but i dont get why he can do newnode

flat pier Oct 20, 2020, 9:42 PM

#

you got the answer here

lusty sand Oct 20, 2020, 9:42 PM

#

You are trying to reassign the setNext method to be the node, instead of calling the setNext method with the node
@desert cedar this one?

vocal gorge Oct 20, 2020, 9:43 PM

#

like said above, you can't do ._next on a string, because strings don't have this attribute (duh). Wrap the string in a Node first.

flat pier Oct 20, 2020, 9:43 PM

#

the code you are using (or writing) has two concepts: SingleLinkedList which is the container and Node which wraps the actual data with bookkeeping information (next and prev)

desert cedar Oct 20, 2020, 9:43 PM

#

Yeah, you made a node earlier in the function, use that instead of the string.

flat pier Oct 20, 2020, 9:43 PM

#

you can’t just add a string to the List, you have to add a Node

#

something like new = self._Node(element, currentNode) prevNode._next = new

olive vine Oct 20, 2020, 9:44 PM

#

cur.setNext(node) ?

lusty sand Oct 20, 2020, 9:44 PM

#

holy shit it worked!

flat pier Oct 20, 2020, 9:44 PM

#

or that, if you have a method then use that instead of changing internal data directly

lusty sand Oct 20, 2020, 9:44 PM

#

📎 unknown.png

flat pier Oct 20, 2020, 9:45 PM

#

(but that code is strangely written, it is not very idiomatic for Python)

lusty sand Oct 20, 2020, 9:49 PM

#

I really appreciate the feedback honestly

#


counter = 0 
    while True:
        if counter == i:
            prevNode._next = node
            node._next = currentNode
            print('Adding # ', self._size, ' element: ', node.getElement())
            break
        prevNode = node
        currentNode = node._next
        counter += 1 ```

#

some odd reason it's skipping the if statement

flat pier Oct 20, 2020, 9:51 PM

#

must be because counter is never equal to i

#

add print to see what’s going on!

lusty sand Oct 20, 2020, 9:58 PM

#

counter = 0 
    while True:
        if counter == i:
            prevNode._next = node
            node._next = currentNode
            print('Adding # ', self._size, ' element: ', node.getElement())
            break
        prevNode = node
        currentNode = node._next
        print(counter)
        counter += 1 ```

#

so this is with the print statements and it is equating to the i variable

flat pier Oct 20, 2020, 9:58 PM

#

no, print counter and i before the if, otherwise you won’t see anything!

lusty sand Oct 20, 2020, 10:01 PM

#

A3trans = ('A,Washington',
           'A,Adams',
           'A,Jefferson',
           'A,Madison',
           'A,Monroe',
           'A,Quincy Adams',
           'A,Jackson',
           'A,Van Buren',
           'A,Harrison',
           'A,Tyler',
           'A,Polk',
           'A,Taylor',
           'A,Fillmore',
           'A,Pierce',
           'A,Buchanan',
           'A,Lincoln',
           'A,AJohnson',
           'A,Grant',
           'A,Hayes',
           'A,Garfield',
           'A,Arthur',
           'A,Cleveland',
           'A,Harrison',
           'A,Cleveland',
           'A,McKinley',
           'A,TRoosevelt',
           'IE,Wilson,A,TRoosevelt',
           'IE,Taft,B,Wilson',
           'A,Coolidge',
           'R',
           'R',
           'R',
           'A,Harding',
           'IE,Wilson,B,Harding',
           'A,Coolidge',
           'A,FDRoosevelt',
           'IE,Hoover,B,FDRoosevelt',
           'IA,2,Shuman',
           'IA,40,Kennedy',
           'A,LBJohnson',
           'IE,Nixon,A,LBJohnson',
           'IE,Eisenhower,B,Kennedy',
            'IE,Truman,B,Eisenhower') ```

#

📎 unknown.png

#

it says it's appending to the linked list, but when i call the showList function. it's not showing up

wraith valve Oct 20, 2020, 10:35 PM

#

r u like looping through a linked list

glossy jay Oct 20, 2020, 11:36 PM

#

Hi all,
Sorry if this is the wrong channel to ask this:
I have a nested loop inside a nested loop (with all three loops having a range of 50). In the innermost loop, I have a code that takes the combo of i, j, k and runs a method, which takes 3 seconds. This means there are 125,000 combinations, with a 3 s runtime for each... how do I approach running this in a way that won't take days? Should I spawn 10 threads in the innermost loop so that the time is reduced by a fifth for each run of the inner loop? Is there an easier way that I'm missing? Thanks!

agile sundial Oct 20, 2020, 11:40 PM

#

there's itertools.combinations

finite lava Oct 20, 2020, 11:49 PM

#

you need to use [ ] not ( ) if you want a list returned

#

and there's no point in initialising elem1 and elem2

agile sundial Oct 20, 2020, 11:50 PM

#

there aren't tuple comprehensions

thin otter Oct 20, 2020, 11:52 PM

#

maybe replace the () for the tuple with [] for a list to use list comprehensions, then wrap that instde a call to tuple()?

flat pier Oct 21, 2020, 1:44 AM

#

you want a tuple of tuples? return tuple((elem1, elem2) for etc etc )

quick tapir Oct 21, 2020, 1:52 AM

#

        lines = Image.new("1",(w,h),1)
        linesDrawer = ImageDraw.Draw(lines)
        radius = max(w,h)*1.5
        for point in [(radius*cospi(1/12*i*2),radius*sinpi(1/12*i*2)) for i in range(12)]:
            linesDrawer.line([(w/2,h/2),point],fill="black",width=ceil((w+h)/1000))```This script is supposed to generate lines from the center of a rectangle to 12 points on a circle that encapsulates that ractangle to produce 12 equally sized angles, but the only thing that I can't seem to get to properly work is the sizing of the angles- no matter how hard I try, one side will have larger angles than another, and I can't understand why this might be happening. To clarify, `w` is the width of the rectangle and `h` is the height of the rectangle. Any ideas what I've done wrong?

#

Here's what the code above produces, which is the closest I've been able to get https://cdn.discordapp.com/attachments/763591770369818624/768288143463284736/output.png

void cliff Oct 21, 2020, 2:44 AM

#

Hey guys

#

is there a way to have [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)] in one line?

#

here's my code

#

a = np.ones((5,1), dtype=[('a', 'i4'), ('b', 'i4'),('c', 'i4'),('d', 'i4'),('e', 'i4')]) print(a)

flat sorrel Oct 21, 2020, 2:58 AM

#

technically [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)] is one line xD

quick tapir Oct 21, 2020, 2:59 AM

#

Yeh that's what I was confused about originally lol

void cliff Oct 21, 2020, 3:00 AM

#

no i mean

quick tapir Oct 21, 2020, 3:00 AM

#

I know what you mean now, dw

#

You're wanting it to be printed in one line, not as in coded in one line

void cliff Oct 21, 2020, 3:00 AM

#

📎 unknown.png

#

code in one line lol

quick tapir Oct 21, 2020, 3:01 AM

#

Well, new lines are represented as \n in strings

void cliff Oct 21, 2020, 3:01 AM

#

and i want it to be [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)]

quick tapir Oct 21, 2020, 3:01 AM

#

So try just removing all the instances of \n

flat sorrel Oct 21, 2020, 3:01 AM

#

not sure why you want to do that but I guess...

void cliff Oct 21, 2020, 3:01 AM

#

there's no \n here....

quick tapir Oct 21, 2020, 3:01 AM

#

Not in the text lol

void cliff Oct 21, 2020, 3:02 AM

#

this is numpy python structure array

flat sorrel Oct 21, 2020, 3:02 AM

#

str(a).replace('\n', ' ')

quick tapir Oct 21, 2020, 3:02 AM

#

^^^ Exactly

void cliff Oct 21, 2020, 3:02 AM

#

i mean the code

#

not the result in one line

flat sorrel Oct 21, 2020, 3:02 AM

#

!e

import numpy as np

a = np.ones((5, 5), dtype=int)
print(str(a).replace('\n', ' '))

halcyon plankBOT Oct 21, 2020, 3:02 AM

#

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

flat sorrel Oct 21, 2020, 3:03 AM

#

is that what you need?

void cliff Oct 21, 2020, 3:03 AM

#

no i mean

quick tapir Oct 21, 2020, 3:03 AM

#

Are you meaning print(np.ones((5,1), dtype=[('a', 'i4'), ('b', 'i4'),('c', 'i4'),('d', 'i4'),('e', 'i4')]))

#

As in, not having to set it to a variable first before printing it?

void cliff Oct 21, 2020, 3:04 AM

#

This is the existed code

📎 unknown.png

#

and i want to change the result to be

flat sorrel Oct 21, 2020, 3:04 AM

#

use slice assignment

void cliff Oct 21, 2020, 3:04 AM

#

[(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)]

quick tapir Oct 21, 2020, 3:04 AM

#

Ok if you're wanting to change the result then that's not the code, is it lol

#

Me and Darklight have already gave you the answer multiple times

#

print(str(a).replace('\n', ' '))

void cliff Oct 21, 2020, 3:04 AM

#

no lol

quick tapir Oct 21, 2020, 3:04 AM

#

???

flat sorrel Oct 21, 2020, 3:05 AM

#

use slice assignment

#

@void cliff

void cliff Oct 21, 2020, 3:05 AM

#

the picture has the result of [(1, 1, 1, 1, 1),(1, 1, 1, 1, 1)(1, 1, 1, 1, 1)(1, 1, 1, 1, 1) (1, 1, 1, 1, 1)]

#

and i want it to be [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)]

#

how can i change it?

flat sorrel Oct 21, 2020, 3:05 AM

#

Read above

quick tapir Oct 21, 2020, 3:05 AM

#

Ooooh right ok I get you know, sorry lol

void cliff Oct 21, 2020, 3:06 AM

#

📎 unknown.png

#

this is not what i want lol

flat sorrel Oct 21, 2020, 3:06 AM

#

import numpy as np
a = np.ones((5, 5), dtype=int)
a[1:-1, 1:-1] = 0

void cliff Oct 21, 2020, 3:07 AM

#

it doesnt work for me

#

📎 unknown.png

#

btw i have to have names of column

flat sorrel Oct 21, 2020, 3:08 AM

#

why

void cliff Oct 21, 2020, 3:08 AM

#

it's the part of the assignment lol

#

Make a 5x5 array filled with 1's with column names of 'a','b','c','d','e', and types of 32 bit int; do this on only 1 line of code

The output will look like this: [(1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1)]

import numpy as np
a = np.ones((5,1), dtype=[('a', 'i4'), ('b', 'i4'),('c', 'i4'),('d', 'i4'),('e', 'i4')])
print(a)

flat sorrel Oct 21, 2020, 3:08 AM

#

it doesn't really make sense to hollow out the middle of a structured array like that but ok

void cliff Oct 21, 2020, 3:09 AM

#

is my code fine?

flat sorrel Oct 21, 2020, 3:09 AM

#

doesn't it already match the output?

#

I don't get the problem

#

why do you have to assign zeros?

void cliff Oct 21, 2020, 3:10 AM

#

because it is the second question

#

Change every value in it that is not on the edge of a zero; do this on only 1 line of code

The output will look like this: [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)]

a = np.ones((5,1), dtype=[('a', 'i4'), ('b', 'i4'),('c', 'i4'),('d', 'i4'),('e', 'i4')])
a[1:-1, 1:-1] = 0

print(a)

#

so i might be wrong on my 1st question

flat sorrel Oct 21, 2020, 3:12 AM

#

you can still use multiindexing

#

a[['b', 'c', 'd']][1:-1] = 0

void cliff Oct 21, 2020, 3:12 AM

#

oh wow

#

I didnt realize that i can do that

#

thank you so much dark light!

flat sorrel Oct 21, 2020, 3:13 AM

#

np

void cliff Oct 21, 2020, 3:34 AM

#

hey about that assignment again

#

he wants me to Create a view

#

does it affect to the original "a" ?

#

or that view is a copy of "a"

flat sorrel Oct 21, 2020, 3:42 AM

#

you can check that easily by printing the original array afterwards

void cliff Oct 21, 2020, 3:44 AM

#

ok

#

so does he want me to do that if it affects to the original variable

flat sorrel Oct 21, 2020, 3:52 AM

#

look up numpy on what a "view" is

void cliff Oct 21, 2020, 4:02 AM

#

ok got it

#

just last question

#

Create a second view of the first view that shows only the middle 9 places; do this on only 1 line of code

#

📎 unknown.png

#

The output of the 2nd view will look like this: [(1, 0, 1) (1, 0, 1) (1, 0, 1)]

#

oh nvm let me figure it out

#

📎 unknown.png

#

is this right?

flat sorrel Oct 21, 2020, 4:09 AM

#

I guess

#

though you can just chain the two indexes together

void cliff Oct 21, 2020, 4:10 AM

#

what do you mean

#

by chain the two indexes together

flat sorrel Oct 21, 2020, 4:15 AM

#

c = b[1:4][['b', 'c', 'd']]

void cliff Oct 21, 2020, 4:15 AM

#

oh

#

ok thank you for letting me know

verbal acorn Oct 21, 2020, 4:32 AM

#

I need some help with a question

#

https://codeforces.com/contest/1433/problem/F

Codeforces

Problem - F - Codeforces

#

I have tried using 2D DP but i failed to get it AC

eager hamlet Oct 21, 2020, 5:05 AM

#

so when doing dijkstra's can i stop immediately once i reach the end which i was trying to find the lowest cost to

#

(ping 2 reply)

oblique panther Oct 21, 2020, 5:08 AM

#

@eager hamlet no, you have to process every node in the queue

#

otherwise there might be a shorter path that you haven't discovered yet

eager hamlet Oct 21, 2020, 5:13 AM

#

ok then

red estuary Oct 21, 2020, 6:24 AM

#

can anyone suggest me a good place to start learning ds and algo , im familiar with python's buit in data structures , but not user defined ones like trees etc

lilac geyser Oct 21, 2020, 7:59 AM

#

Hello folks, I've a question: how would you look for thousands of strings within a file ?
would you build a big regexp ? another way ?

flat sorrel Oct 21, 2020, 8:02 AM

#

For each word in your file, check against the list of words to match against. The words to match against can be stored in a https://en.wikipedia.org/wiki/Trie to speed up the matching process by reading your word character by character and navigating down the trie accordingly

#

@lilac geyser

lilac geyser Oct 21, 2020, 8:04 AM

#

yeah I was coming to the same conclusion as well

#

thanks for the advice

flat sorrel Oct 21, 2020, 8:04 AM

#

np

coarse bluff Oct 21, 2020, 9:08 AM

#

Currently i'm reading a document and they give the
following hex string in their document 41d56acebac1dd44c1297ad31f6f788abb580bbeda
and i need to convert to this string TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE. Any one know what kind of string TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE is? so i can write a converter

#

it doesn't mention any where in their document believe me i tried

#

nvm i found out it's base58, took a while to convert...

coarse bluff Oct 21, 2020, 9:35 AM

#

anyone know how to convert base58 to hexadecimal in python?

brave oak Oct 21, 2020, 9:38 AM

#

anyone know how to convert base58 to hexadecimal in python?
@coarse bluff you have it as a base-10 int already?

#

or do you need help wit htaht part too

coarse bluff Oct 21, 2020, 9:41 AM

#

so i need to convert from hex string 41d56acebac1dd44c1297ad31f6f788abb580bbeda to this base58 TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE and i can't find a way. In the document i'm reading it tell me that one is hex string and another is base58 , now i need to write a function to convert between those 2 with the result above @@! i'm really bad at string converting at you can see @brave oak

#

like currently from this api https://api.shasta.trongrid.io/v1/accounts/TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE/transactions?only_to=true&min_timestamp=0&only_confirmed=True

#

somehow TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE is 41d56acebac1dd44c1297ad31f6f788abb580bbeda and i need to convert so i can do comparision @@!

#

from trongrid document owner address in base58 or hex

brave oak Oct 21, 2020, 9:42 AM

#

>>> int('41d56acebac1dd44c1297ad31f6f788abb580bbeda', 16)
96216003348366323833159490712672064757310392352474

#

this is the simple part

#

apparently there's a base58 package

#

you can try using that

#

unless you really want to write your own converter

#

which is 🥴

coarse bluff Oct 21, 2020, 9:43 AM

#

well i tried

import base58
hexstring= "41d56acebac1dd44c1297ad31f6f788abb580bbeda"
unencoded_string = bytes.fromhex(hexstring)
encoded_string= base58.b58encode(unencoded_string)
print(encoded_string)

but it came out 53oCBnvf5mnzaJpr94p1BjxNEGq5j instead of TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE

#

i think trongrid documents is just messing with me

brave oak Oct 21, 2020, 9:45 AM

#

hm

#

are you sure the alphabet is the same?

coarse bluff Oct 21, 2020, 9:46 AM

#

well yes you can check the api https://api.shasta.trongrid.io/v1/accounts/TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE/transactions?only_to=true&min_timestamp=0&only_confirmed=True @brave oak , if you replace TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE with 41d56acebac1dd44c1297ad31f6f788abb580bbeda it still return the same result

#

and it's in to_address of the json too

brave oak Oct 21, 2020, 9:46 AM

#

no, I mean

#

the alphabet it uses

#

like to encode base 58

coarse bluff Oct 21, 2020, 9:47 AM

#

i don't know what that is base58 pretty new to me

brave oak Oct 21, 2020, 9:47 AM

#

okay like

#

hexadecimal is traditionally 123456789abcdef, right

coarse bluff Oct 21, 2020, 9:47 AM

#

yeah

brave oak Oct 21, 2020, 9:47 AM

#

but you could conceivably make it 12345678qwertyu

coarse bluff Oct 21, 2020, 9:47 AM

#

i remember how to convert it to binary

#

maybe

brave oak Oct 21, 2020, 9:47 AM

#

so that's a different alphabet

#

still base 16

#

but different characters

coarse bluff Oct 21, 2020, 9:47 AM

#

maybe they use different alphabet

brave oak Oct 21, 2020, 9:48 AM

#

okay so get a known base58 string and int

#

and convert it

#

and see if you get the expected result

#

if you don't, clearly the alphabet is different

coarse bluff Oct 21, 2020, 9:49 AM

#

well i tried
import base58
hexstring= "41d56acebac1dd44c1297ad31f6f788abb580bbeda"
unencoded_string = bytes.fromhex(hexstring)
encoded_string= base58.b58encode(unencoded_string)
print(encoded_string)
but it came out 53oCBnvf5mnzaJpr94p1BjxNEGq5j instead of TVRet35bBbkiEz455NFmLvvtSRMZYCD5nE
@brave oak i know that this doesn't work in python so they must be using different alphabet

#

this is their document i'm reading https://developers.tron.network/reference#transaction-information-by-account-address

TRON Developer Hub

Background

coarse bluff Oct 21, 2020, 10:08 AM

#

@brave oak i think i found trongrid alphabet , from trongrid alphabet code in their github

const ALPHABET = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';

can you check if this is correct ?

coarse bluff Oct 21, 2020, 10:26 AM

#

i finally made the conversion jesus f*cking christ that took the whole afternoon

import base58

to_base58 = base58.b58encode_check(bytes.fromhex("41d56acebac1dd44c1297ad31f6f788abb580bbeda"))

print(to_base58)

ebon yarrow Oct 21, 2020, 10:47 AM

#

Problem
Pattern Matching: You are given two strings, pattern and value. The pattern string consists of just the letters a and b, describing a pattern within a string. For example, the string catcatgocatgo matches the pattern aabab (where cat is a and go is b). It also matches patterns like a, ab, and b. Write a method to determine if value matches pattern.
Brute Force Solution:

We could do this by iterating through all substrings for a and all possible substrings for b. There are O( n^2 )
substrings in a string of length n, so this will actually take O( n^4 ) time. But then, for each value of a and b,
we need to build the new string of this length and compare it for equality. This building/comparison step
takes O(n) time, giving an overall runtime of O(n^5 ).```
Can someone please help me understand what this brute force solution is even trying to do?
```for each possible substring a
    for each possible substring b
      candidate = buildFromPattern(pattern, a, b)
      if candidate equals value
        return true```

#

please tag me to notify

candid osprey Oct 21, 2020, 12:07 PM

#

@ebon yarrow the brute force approach is simply taking all possible subsets of the main string first. Then, for each pair of possible subsets it uses the pattern to construct back "some" string. For example, if the pattern was aabab for catcatgocatgo, then the brute force first takes a random substring. Say it takes "at" and "o". Then it constructs the pattern version of this string. "atatoato" (note, aabab). Then it compares this vs main string "catcatgocatgo". Mismatch? Keep going.

wicked pebble Oct 21, 2020, 12:28 PM

#

@ebon yarrow I dont know if this would help, but what I would do is take advantage of the fact that there are only ‘a’ and ‘b’ in the pattern. What I mean is, all string ‘a’s and all string ‘b’s will have the same length, respectively. So, I would first count the ‘a’s and ‘b’s in the pattern and then check to see if you can make a combination of the length of the value with a combination of {len(a) * (number of times a appears) + len(b) * (number of times b appears)} . You could easily do this by starting from 1, set the len(a) to an integer and if {len(value) - len(a) * (how many times a appears)} is divisible by (number of times b appears), there you have a set of lengths for string a and b.

#

Next, according to the pattern and lengths for a and b, you can get the as and bs using string slicing. For instance, in ‘catcatgocatgo’ and ‘aabab’, you have 3 as and 2 bs that make up a combination of 13 letters. Using the mentioned algorithm, you have a set of (1, 5) , (3, 2) for the lengths of a and b(because 1 * 3 + 5 * 2 = 13). Taking the set (1,5), because the pattern is aabab, you first get the first string that consists of 1 letter and save it, which is ‘c’ in ‘catcatgocatgo’. Then, there’s another a in the pattern so you get the second string with length 1, which is ‘a’. However, our previously saved value of string a is ‘c’, not ‘a’, so you break out of the loop for this set (1,5).

#

Checking all the sets ( like the (1,5) and (3,2) ), if any of them can pass( meaning all string ‘a’s match and all string ‘b’s match ), you return True. If by the end, none matches, you return False.

wicked pebble Oct 21, 2020, 12:59 PM

#

Time complexity : In the first part, since number operations take no time, it takes O(len(value)) time. In the second, in each iteration of each set, you slice the values according to the pattern and check if all ‘a’s and all ‘b’s match, so the worst case scenario for this iteration is O(len(value)). Also, the maximum number of sets we can get is len(value)/2 (Now that I think about it, if you think about a pattern like ‘ab’, it always matches so you should have a if statement saying if the number of times a and b appear is 1 each, you return True. But if you think of a pattern like ‘aab’, you have len(value) / 2 times that you get the value a and since b is just 1* any number, you can make a combination for all len(value)/2 ‘a’s. So max time complexity for number of sets is len(value)/2). To sum up, the worst case scenario is O(len(value) ^ 2), but usually it would take much less because you don’t get that many sets.

#

Now this is a BIG improvement from n^5

wicked pebble Oct 21, 2020, 2:39 PM

#

Do you want a test code?

wicked pebble Oct 21, 2020, 4:41 PM

#

Actually, here's the repl.it code @ebon yarrow

#

https://repl.it/@ThomasKim5/TruthfulDeficientMachinecode#main.py

repl.it

ThomasKim5

TruthfulDeficientMachinecode

A Python repl by ThomasKim5

#

from collections import Counter

def PatternMatching(pattern, val):
  if pattern == 'ab' or pattern == 'ba':return False

  count = Counter(pattern)
  n = 1
  validSets = []

  while n * count['a'] < len(val):
    if (len(val) - (n * count['a'])) % count['b'] == 0:
      validSets.append((n, int((len(val) - (n * count['a'])) / count['b'])))
    n += 1

  for s in validSets:
    a, b = '', ''
    n = 0
    notValid = False

    for p in pattern:
      if p == 'a':
        if a == '':
          a = val[n:n + s[0]]
        elif val[n:n + s[0]] != a:
          notValid = True
          break
        n += s[0]

      elif p == 'b':
        if b == '':
          b = val[n:n + s[1]]
        elif val[n:n + s[1]] != b:
          notValid = True
          break
        n += s[1]

    if not notValid:
      return True

  return False

#

in this code,

print(PatternMatching('aabab', 'donaldtrumpdonaldtrumpfuckdonaldtrumpfuck'))

which is in the repl.it, you can see it returns True

#

You can easily see it's O(n^2) in the code.

boreal linden Oct 21, 2020, 4:44 PM

#

Can someone remind me what the |l X - m l|^2 meant in K means? it is not the eucledian distance or is it?

📎 unknown.png

fair summit Oct 21, 2020, 4:55 PM

#

it is

wraith valve Oct 21, 2020, 4:58 PM

#

i have a feeling its the square of the euclidian distance or sth along that line

#

it looks like its sth that goes and minimizes distances

fair summit Oct 21, 2020, 4:59 PM

#

euclidean distance is already defined as sqrt(map(square, xs))

wraith valve Oct 21, 2020, 5:00 PM

#

from my understanding k means just simply minimizes distance

fair summit Oct 21, 2020, 5:00 PM

#

formally, ||x||^2 is the l2-norm, which is basically euclidean distance

#

it's also called euclidean distance, for a good reason

wraith valve Oct 21, 2020, 5:00 PM

#

which makes sense in this case

fiery cosmos Oct 21, 2020, 7:26 PM

#

How can I read in a binary file and convert the byte string to a normal string but still maintain the character placement

agile sundial Oct 21, 2020, 7:27 PM

#

is what normal

knotty gate Oct 21, 2020, 7:27 PM

#

Wrong place

#

Sry

rare dawn Oct 21, 2020, 8:40 PM

#

Does anyone know a good data structure and algorithm course i can take?

main gorge Oct 21, 2020, 8:45 PM

#

M.I.T. has an an online course that helped my not fail my ds and algo class.

#

free.

rare dawn Oct 21, 2020, 8:46 PM

#

where can I find it ?

#

@main gorge Coursera?

agile sundial Oct 21, 2020, 8:47 PM

#

mit ocw

charred basalt Oct 21, 2020, 8:49 PM

#

yeah that mit ocw algorithm course is fantastic https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-006-introduction-to-algorithms-fall-2011/

MIT OpenCourseWare

Introduction to Algorithms

This course provides an introduction to mathematical modeling of computational problems. It covers the common algorithms, algorithmic paradigms, and data structures used to solve these problems. The course emphasizes the relationship between algorithms and programming, and int...

fading raptor Oct 22, 2020, 5:17 AM

#

Can I ask calculus questions ?

fiery cosmos Oct 22, 2020, 5:18 AM

#

yes ofcourse all math, algorithm, general cs is this channels topic

fading raptor Oct 22, 2020, 5:19 AM

#

Great !

#

I'm currently studying limits, But I still don't get what can I use it for irl ?

#

Or in ML for example, Since I'm studying for ML and DS

eager hamlet Oct 22, 2020, 5:21 AM

#

limits -> derivatives -> ml

fiery cosmos Oct 22, 2020, 5:22 AM

#

Studying Limits for ML is good, but you don't apply it directly in ML or DS, you apply it indirectly by computing derivatives for some algorithm, also I think you will see statistics more than calculus in ML or Data-science

fading raptor Oct 22, 2020, 5:23 AM

#

I know a lot of statistics, Like a decent amount of knowledge
But calculus, I heard it's so important for ML

#

And

#

Could you give me an irl example about limits ?

eager hamlet Oct 22, 2020, 5:23 AM

#

haha import tensorflow as tf go brrr

#

but uh

#

it's mostly just for understanding backpropagation iirc

fading raptor Oct 22, 2020, 5:23 AM

#

backpropagation ?

fiery cosmos Oct 22, 2020, 5:24 AM

#

Yeah gradient descent algorithm which has calculus in it.

fading raptor Oct 22, 2020, 5:24 AM

#

I will take a look at it

wraith valve Oct 22, 2020, 5:39 AM

#

multi var calc go brrrr

cobalt sedge Oct 22, 2020, 7:28 AM

#

Could anyone help me with this??

Given a set of n distinct non-negative integers, we wish to find the k smallest integers in the set and output them in sorted order.
Three possible algorithms are suggested for solving this problem. For each algorithm, analyze its worst case running time and state that running time in terms of both n and k.

(a) Given n unsorted integers from the range [0, n2 − 1], output the k smallest numbers in sorted order using radix sort. We assume that integers up to O(n^2) can be stored in a computer word.

(b) Sort all n integers by Insertionsort, and output the k smallest numbers in sorted order.

(c) Build a heap on the n integers and call Extract-Min k times. For this part, you may assume that you can build a data structure heap on n items in O(n) time.

mossy kettle Oct 22, 2020, 8:39 AM

#

hi, is there a program to test a pseudocode?

low palm Oct 22, 2020, 8:42 AM

#

Test pseudocode? No, pseudocode isn't code. It can be written in whatever form you like. I don't think AI is there yet @mossy kettle

mossy kettle Oct 22, 2020, 8:42 AM

#

lemon_sentimental

wicked pebble Oct 22, 2020, 8:48 AM

#

I mean, pseudocode is almost identical to Python, so maybe do just little tweaks like spacing and colons?

fiery cosmos Oct 22, 2020, 9:22 AM

#

@FuckYouMath2411#3292 do you know what these algorithms are specified in a, b, c?

cobalt sedge Oct 22, 2020, 10:00 AM

#

U mean radix sort, insertion sort and heap sort of extract-min?

fiery cosmos Oct 22, 2020, 10:01 AM

#

yes

cobalt sedge Oct 22, 2020, 10:01 AM

#

I know them all but i've no idea how to do it....

#

I know how they work

fiery cosmos Oct 22, 2020, 10:01 AM

#

Did they ask you to code or just explain?

cobalt sedge Oct 22, 2020, 10:01 AM

#

just state the running time

fiery cosmos Oct 22, 2020, 10:07 AM

#

a. idk about radix sort you can google it up

b. insertion sort has O(n^2) worst time complexity, and after sorting you are taking K- elements which will take O(K) time, so O(n^2) is bigger term than O(K), hence the worst case running time of the algorithm is O(n^2)

c. building a heap of n-numbers takes O(n) worst time complexity and then you are calling K-times a extract min operation where each operation takes O(log n) worst time complexity totalling O(K log n), now among O(n) and O(K log n), O(k log n) term is bigger hence the worst case running time of the algorithm is
O(K log n)

cobalt sedge Oct 22, 2020, 10:10 AM

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ohhhh, is it like actually the worst case running time is just the time of using those algorithm to sort items?

#

as most of the time, it would be larger than the time of log(k), which log(k) is the time to take the k-elements

#

Do I interpret it correctly?

fiery cosmos Oct 22, 2020, 10:13 AM

#

as you can see in c building the heap cost us O(n) time whereas extracting k-items cost us O(k log n) time which is greater than building the whole heap itself

cobalt sedge Oct 22, 2020, 10:13 AM

#

oh i see

#

ok thanks

fiery cosmos Oct 22, 2020, 10:13 AM

#

So the final goal is to express the worst case time complexity of "Extracting K-items from a list"

#

maybe the sorting takes more time, or maybe extracting those k takes more times after doing some "smart" algorithm

cobalt sedge Oct 22, 2020, 10:15 AM

#

okay thank you very much

fringe mortar Oct 22, 2020, 11:01 AM

#

;compile python

rare dawn Oct 22, 2020, 12:58 PM

#

Given an integer product, find the smallest positive (i.e. greater than 0) integer the product of whose digits is equal to product. If there is no such integer, return -1 instead.

Example

For product = 12, the output should be
digitsProduct(product) = 26

#

i need some help in finding a good algorithm for this

mint jewel Oct 22, 2020, 12:59 PM

#

I would start with prime factorization

agile sundial Oct 22, 2020, 12:59 PM

#

my first thought was that too

#

then stick them together

mint jewel Oct 22, 2020, 1:00 PM

#

though you would have to special case 4, 6, 8, 9

agile sundial Oct 22, 2020, 1:01 PM

#

right because 22 > 4

rare dawn Oct 22, 2020, 1:03 PM

#

the first thing i did was check if the number was prime or not

#

cuz if it was prime it should return -1

agile sundial Oct 22, 2020, 1:04 PM

#

yeah, that makes sense

wicked pebble Oct 22, 2020, 1:31 PM

#

You could utilize Eratosthenes' sieve

#

To make it more efficient

fiery cosmos Oct 22, 2020, 2:26 PM

#

@rare dawn how large can that product be?

rare dawn Oct 22, 2020, 2:29 PM

#

0-600

#

i solved it

fiery cosmos Oct 22, 2020, 2:30 PM

#

just 3 digits are enough

#

run a three for loop

rare dawn Oct 22, 2020, 2:30 PM

#

i just keep dividing by the largest digit i can

fiery cosmos Oct 22, 2020, 2:31 PM

#

that also works 👍

rare dawn Oct 22, 2020, 2:31 PM

#

until it becomes 1

#

thanks anyway 👍

void cliff Oct 22, 2020, 3:25 PM

#

Have the user input a list of columns for a table

Have the user input a data type for every column: int, float, string size 255

In a loop have the user input the values for each row

Ensure the string size doesn't exceed 255

Print the results when the user is finished
for the second sentence, how do you know when the user has already input every column include int , float , string size 255?

fiery cosmos Oct 22, 2020, 3:27 PM

#

you check if you can cast the input given to the datatype that you have taken

#

if not you raise error

void cliff Oct 22, 2020, 3:31 PM

#

do you mean by type(a) ?

#

a = input("....") a is going to be a string how do you know if a is either int , float, string size 255

fiery cosmos Oct 22, 2020, 3:33 PM

#

yeah you do

try:
  casted = int(a)
except Exception:
  print('invalid data')

#

you don't need a check for string, since you take input itself as string

void cliff Oct 22, 2020, 3:34 PM

#

btw is string size 255 bytes or length?

fiery cosmos Oct 22, 2020, 3:35 PM

#

I don't know tbh

#

maybe length

void cliff Oct 22, 2020, 3:47 PM

#

import numpy as np a = int(input("Size of array:")) lst = [] for i in range(a): my_array.append((input("Values:"))) my_array = np.array(my_array) print(my_array)

#

i got this already i dont know what to do next

fiery cosmos Oct 22, 2020, 5:27 PM

#

What do you want to achieve @void cliff

gaunt forge Oct 22, 2020, 5:28 PM

#

Uh, strings in python are weird

fiery cosmos Oct 22, 2020, 5:28 PM

#

Oh you are the same person lol

gaunt forge Oct 22, 2020, 5:28 PM

#

You don't want to get the size in bytes of string in python

fiery cosmos Oct 22, 2020, 5:28 PM

#

(Tommy)

gaunt forge Oct 22, 2020, 5:29 PM

#

Every strong stores an additional 49-80 bytes of memory like hash, length, length in bytes, encoding type, and string flags

#

and the string itself depends on how long it is

naive cloak Oct 22, 2020, 5:55 PM

#

Basic OOP question: Why is it not necessary to define 'other' in population_density()? Isn't population_density() computed with everything belonging to self?

` class something:

def population_density(self) -> float:
return self.population / self.area

def has_higher_population_density(self, other) -> bool:

    return self.population_density() > other.population_density()

`

fiery cosmos Oct 22, 2020, 6:04 PM

#

other is defined

#

def has_higher_population_density(self, other)

#

ignore oop, just think about functions

#

other is an arg that is past to this function when it is called

naive cloak Oct 22, 2020, 6:11 PM

#

@fiery cosmos do you mean other is passed to population_density() (so now other is used instead of self, becoming when called population_density(other))?

fiery cosmos Oct 22, 2020, 6:11 PM

#

its just a function

#

ignore oop

#

def hello(arg1):
  print(arg1)```

#

same as this

#

you call with hello('hi')

#

it prints hi

naive cloak Oct 22, 2020, 6:14 PM

#

wouldn't it then be population_density(self) > population_density(other)?

fiery cosmos Oct 22, 2020, 6:17 PM

#

well id assume 'other' in this case is supposed to be another instance of that class

#

and therefore they both have their own population_density() function

naive cloak Oct 22, 2020, 6:24 PM

#

@fiery cosmos So when defining other inside a method it can become an instance and have then it's own functions (substituting self with other)?

fiery cosmos Oct 22, 2020, 6:24 PM

#

what

#

no

#

do you understand basic python functions or are you starting with classes

naive cloak Oct 22, 2020, 6:25 PM

#

I understand basics

#

so also functions I think

fiery cosmos Oct 22, 2020, 6:26 PM

#

ok, this is literally the same scenario as a standard function i posted above. other is an arg. when you call has_higher_population_density() you need to call it with has_higher_population_density(arg1)

#

for instance here i will give an example that has its own functions...

#

!e python def test(other): print(other.split(',')) test('hello,world')

halcyon plankBOT Oct 22, 2020, 6:28 PM

#

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

fiery cosmos Oct 22, 2020, 6:29 PM

#

same idea, and you can access the split of the 'string' object

#

so in the oop you posted, they are passing an object into other, and inside of the function, they can access the any methods on other

#

namely in this case, others population_density()

naive cloak Oct 22, 2020, 6:54 PM

#

I get a bit more now, but I'm not sure about self.population/self.area in relation to other.population_density(), does it return other.population/other.area?

fiery cosmos Oct 22, 2020, 6:57 PM

#

'string1' and 'string2' are both instances of string class

#

they both have their own unique split method

#

in the code you posted, has_higher_population_density is a method of class something

#

so for instance, lets say python one = something() two = something()

#

now i can call one.has_higher_population_density(two)

#

it will run ones has_higher

#

other will be 'two'

#

two(other) and one(self) have their own unique .population_density()

#

one = something()
one.population_density()
two = something()
two.population_density()```

#

no different than like here outside of the function

rare dawn Oct 22, 2020, 8:21 PM

#

Construct a square matrix with a size N × N containing integers from 1 to N * N in a spiral order, starting from top-left and in clockwise direction.

Example

For n = 3, the output should be

spiralNumbers(n) = [[1, 2, 3],
[8, 9, 4],
[7, 6, 5]]

#

can anyone help me with the algorithm to solve this

pure slate Oct 22, 2020, 8:23 PM

#

That sounds like something for the help channels 🤔 But you can write a function like a small state machine.

naive cloak Oct 22, 2020, 8:25 PM

#

@fiery cosmos I don't completely understand that, but I can't wroking anymore on it today. Thanks for everything though, I really do appreciate your help! Once I've studied more on my own I'll definitely refer back to what you explained.

terse prairie Oct 22, 2020, 10:35 PM

#

hello

#

i need count de time of the cpu

#

what is the code or library?

vocal gorge Oct 22, 2020, 10:47 PM

#

time

fiery cosmos Oct 23, 2020, 12:04 AM

#

Hi guys, i have a question:
What is the best practice? What is your opinion about this functions.
I have 2 function, the first return True or False, if can make the action.
The second, it's the same of first, but create and save the file, and return the route of the file.
The function are very similar but the return it's diferent, it's a good practice

📎 unknown.png

brave oak Oct 23, 2020, 12:14 AM

#

Hi guys, i have a question:
What is the best practice? What is your opinion about this functions.
I have 2 function, the first return True or False, if can make the action.
The second, it's the same of first, but create and save the file, and return the route of the file.
The function are very similar but the return it's diferent, it's a good practice
@fiery cosmos ...don't think that's a good idea

#

instead of catching the error and returning False, don't return anything and just let the caller catch the error.

final fjord Oct 23, 2020, 12:40 AM

#

Good evening, I am hoping someone can help straighten me out here. I am writing a blackjack program for school and I am having some issues with things as I have them. If the player chooses to "stay", the program ends and doesnt continue into the dealer section, if the player chooses "hit" it turns into an endless repeat of the current total. I have rearranged things and changed some things that I thought were causing an issue, but I havent had much luck. If I fix a problem, it causes another.

📎 unknown.png

#

and the total never gets changed after the inital 2 cards.

brave oak Oct 23, 2020, 12:51 AM

#

Good evening, I am hoping someone can help straighten me out here. I am writing a blackjack program for school and I am having some issues with things as I have them. If the player chooses to "stay", the program ends and doesnt continue into the dealer section, if the player chooses "hit" it turns into an endless repeat of the current total. I have rearranged things and changed some things that I thought were causing an issue, but I havent had much luck. If I fix a problem, it causes another.
@final fjord your control flow is wrong.

#

conceptually, it should be something like this.

#

during the player's turn:

#

check what actions they are allowed to take, based on their total
if there are any valid actions, take player input to determine what action to take
execute the action
loop

#

you can see that you never update player_total.

final fjord Oct 23, 2020, 12:57 AM

#

I see some of it, I fixed where I was not updating the total.

#

i think it should be
"if total less than 21:
do you want to draw a card
etc
etc
elif total > 21:
print(you lost)
else:
print(you won)

brave oak Oct 23, 2020, 1:01 AM

#

ye

#

you want those checks in a while loop

final fjord Oct 23, 2020, 1:01 AM

#

right
"while total less than 21:
etc
etc"

#

so i generally have the right things, just in the wrong order

final fjord Oct 23, 2020, 1:18 AM

#

thank you very much @brave oak I think I have worked out the kinks

#

there is another thing that was tripping me up. I used the top tuple for simplicity, but how could I use the bottom format and have integers assigned to "J,Q,K,A"

📎 unknown.png

#

the instructions said to use a tuple of strings, but It was not obvious to me how to use that.

📎 unknown.png

fiery cosmos Oct 23, 2020, 1:25 AM

#

you can map these to some numbers

#

since all those are strings

#

📎 unknown.png

final fjord Oct 23, 2020, 1:26 AM

#

can i do
cards = ("A" = 11, "J" = 10, "Q" = 10, "K" = 10)

fiery cosmos Oct 23, 2020, 1:26 AM

#

no ig

#

you can do it like
card_map = dict()

#

and then set card_map["J"] = 10 and so on..

final fjord Oct 23, 2020, 1:28 AM

#

ok

vocal gorge Oct 23, 2020, 1:28 AM

#

or just, well

#

card_map = {"J":10, "A":11,#and so on}

final fjord Oct 23, 2020, 1:31 AM

#

ok cool, thank you very much

vocal gorge Oct 23, 2020, 1:47 AM

#

I mean, sure - when you find a pair of matching chars, delete them. Proceed until either both words end or you end up unable to match a letter to the other word.

#

complexity would be O(n^2) or so

#

sure, or at least changing it

#

oh, there's actually a really simple way

#

for each character in the first string, count the number of this character in the first and second strings, make sure they match

#

then the same for each char in the second string.

#

hmm, now that I think of it...
I wonder if the following is true:
x_1 + x_2 + ... + x_n = y_1 + y_2 + ... + y_n
x_1^2 + x_2^2 + ... + x_n^2 = y_1^2 + y_2^2 + ... + y_n^2
...
x_1^n x_2^n + ... + x_n^n = y_1^n + y_2^n + ... + y_n^n

Is the only solution of this system "y is a permutation of x"?

#

no, not this

#

a system of n equations for n variables

#

like, for n=2:
x_1+x_2 = y_1+y_2
x_1^2+x_2^2 = y_1^2+y_2^2

#

are the only solutions (x_1,x_2) and (x_2,x_1)?

#

for this system, wolfram tells me it is

#

but I wonder if it's true for arbitary n

#

because if yes, it's a way of checking anagrams

#

compare the sum of character indexes, the sum of squares of character indexes, the sum of cubes, and so on

#

if and only if they are all equal, the words are anagrams

#

def my_cool_anagram_checker(a:str,b:str)->bool:
    # In Soviet Russia, we don't use "sets" for this.
    n = len(a)
    if len(b)!=n: return False
    def sum_k(s,k):
        return sum(map(lambda char: ord(char)**k,s))
    return all(sum_k(a,k)==sum_k(b,k) for k in range(1,n+1))

#

>>> my_cool_anagram_checker("hello","asdas")
False
>>> my_cool_anagram_checker("hello","heoll")
True

#

summing can be done with loops too 😛

ocean yacht Oct 23, 2020, 3:19 AM

#

hello, I am still new to algorithm.

#

I am planning to build a recommendation system, maybe just a basic one

#

Can any one give me some helpful recommendation on how should I start and what method should I use, things like that.

#

I plan to use the feedback and ratings for others users as the data for the recommendation

keen hearth Oct 23, 2020, 4:03 AM

#

Seems like that would be a better fit for the #data-science-and-ml channel @ocean yacht

rigid crag Oct 23, 2020, 9:55 AM

#

hi

brittle narwhal Oct 23, 2020, 1:46 PM

#

Can someone please explain why sometimes tuples are used instead of lists?

mint jewel Oct 23, 2020, 1:48 PM

#

tuples are hashable, which means you can use them as keys in a dict, for some algorithms, especially combinatorial ones, you also put tuples representing choices into set to prevent duplicate choices

brittle narwhal Oct 23, 2020, 1:50 PM

#

Can you dumb that down a little.. I haven't learned hashes, dicts and algorithims yet haha

agile sundial Oct 23, 2020, 1:50 PM

#

sometimes the immutability of tuples is a great property, and it makes them better than lists in some cases

fiery cosmos Oct 23, 2020, 1:51 PM

#

When you wank to fix some sequence which you don't want to modify later on you can use tuple

brittle narwhal Oct 23, 2020, 1:51 PM

#

Can you give me an example of where tuples would be better than lists?

wraith valve Oct 23, 2020, 4:56 PM

#

idk maybe like a constant value or sth

brisk haven Oct 23, 2020, 6:24 PM

#

https://www.credit-suisse.com/pwp/hr/en/codingchallenge/#/howtoplay/?promocode=ayushpattnaik

Global Coding Challenge

The Global Coding Challenge is a inter-university online coding competition between students across the globe.

gray heath Oct 23, 2020, 10:45 PM

#

Hi!

#

Can somebody help me, please?

#

I was working with an exercise and the numbers which were generated by the program weren't going to a list I made...

vernal venture Oct 23, 2020, 11:47 PM

#

@gray heath Can you provide the code

brave oak Oct 23, 2020, 11:52 PM

#

Can someone please explain why sometimes tuples are used instead of lists?
@brittle narwhal conceptually they're different

#

tuples are used to group data where position has inherent meaning

#

lists , on the other hand, are used to group data of a common type

#

at least, theoretically.

#

so the example I always use is a 2D point: (x, y)

#

if you reverse the order ((y, x)), it's a different point entirely

#

on the other hand, if you had a collection of points [(x1, y1), (x2, y2), (x3, y3)], position does not give any point meaning beyond "first", "second", or "third".

#

and in particular, note that it makes sense to append to a list because you'd just be adding another object of the same type

#

but not to a tuple because each field has a meaning, and you'd be changing the meaning of the tuple itself.

halcyon plankBOT Oct 24, 2020, 1:27 AM

#

:incoming_envelope: :ok_hand: applied mute to @tepid python until 2020-10-24 01:37 (9 minutes and 58 seconds) (reason: burst rule: sent 8 messages in 10s).

oblique panther Oct 24, 2020, 1:29 AM

#

@brave oak I can see where you're going but if you sort a list, you're imposing a specific order, but you wouldn't convert the list to a tuple when you do that.

keen hearth Oct 24, 2020, 1:49 AM

#

The most significant difference between a tuple and a list in python is that tuples are immutable. This just means that after creating a tuple, you cannot change its elements.

#

Lists, on the other hand, are mutable, meaning the elements of a list can be changed (mutated) after creating it.

#

One downside of mutability, and hence a reason why you might use a tuple in place of a list, is that care needs to be taken when dealing with mutable data. If you have two references to the same list, modifying one will also modify the other.

#

This is often desirable behaviour, but can also cause really hard to track down bugs.

#

Because you have to understand not just the value of the data, but the network of references that exist within the data.

#

Here's an example of mutability: http://pythontutor.com/visualize.html#code=xs %3D [1, 2, 3] ys %3D xs zs %3D xs.copy() print(ys %3D%3D xs) print(ys is xs) print(zs %3D%3D xs) print(zs is xs) ys.append(4)&cumulative=false&curInstr=0&heapPrimitives=nevernest&mode=display&origin=opt-frontend.js&py=3&rawInputLstJSON=[]&textReferences=false

#

Also, mutable objects are not hashable, which essentially means that they cannot be added to sets, or used as dictionary keys.

#

When you add a key to a dictionary, it uses a hash (a number calculated based on the value) to decide where to store it in memory. Later, when you look up the key, the hash is used to find it. But, that means the hash has to be the same as it was originally, which means that the value of the key must not have mutated.

formal sluice Oct 24, 2020, 3:05 AM

#

Sorts

agile sundial Oct 24, 2020, 3:07 AM

#

what sort of sorts

brave oak Oct 24, 2020, 3:12 AM

#

@brave oak I can see where you're going but if you sort a list, you're imposing a specific order, but you wouldn't convert the list to a tuple when you do that.
@oblique panther yes, but there still is no meaning inherent in the order; semantically, it’s the same data type.

#

note also differences in type hinting.

#

for tuples you usually specify one type per field, in line with the idea that each field has its own unique meaning

#

on the other hand, you do not (and cannot, actually) do the same for lists

#

of course, this distinction has a lot more meaning in a statically typed language (especially a more functional one).

#

in Python, you can choose to be guided purely by practicality (mutability).

bronze sail Oct 24, 2020, 7:58 AM

#

is there any algorithm for some games of life?

#

for example having some swarm and each individual is moving on its own to some food

cobalt sedge Oct 24, 2020, 8:57 AM

#

I got a question, the only way i can think of is sort by merge sort or other sort that with O(nlogn) time, could we sort it in O(n) time?

You want to sort m students’ names in the alphabetical order (i.e., a < ab < b). The lengths of their names are not necessarily identical, and the sum of the lengths of names is n. Let A be an array of their names, A = [A1,A2,...,Am], and for any name Ai, it is an array of characters, Ai = [ai1,ai2,...]. The characters are from extended ASCII code, so there are 256 possible characters.
Design an algorithm that sorts the names in O(n) time. Provide the time complexity analysis of your algorithm.

wispy sierra Oct 24, 2020, 9:43 AM

#

"the lengths of names is n" if this mean that N = len(A1) + len(A2)... then you could check out Radix Sort. the time complexity is O(m*k) which m is the number of student and k is the largest length of student's name

#

@bronze sail I think it would depend on how complexity of your games. if there is no obstacles on the way then just simply calculate the angle between the swarm and the food the let the swarm head towards the food follow the calculated angle. if there is wall of any obstacles between then perhaps apply some path-finding algorithms (swarm is the starting point and food is destination)

cobalt sedge Oct 24, 2020, 10:16 AM

#

@wispy sierra Thanks for your help, but I thought the total running time of radix sort is O(d(n+k)), where d is number of digits, n is number of integers and k is values of the digits can take, so if I use radix sort in this question, isnt it be O(256(m+k))?

fiery cosmos Oct 24, 2020, 10:24 AM

#

yeah as you already know the upper-bound which is a constant you can achieve O(n) sort

#

check this algorithm too
https://www.geeksforgeeks.org/counting-sort/

GeeksforGeeks

Counting Sort - GeeksforGeeks

Counting sort is a sorting technique based on keys between a specific range. It works by counting the number of objects having distinct key values

wispy sierra Oct 24, 2020, 10:31 AM

#

So if we have k as the largest length of name, which means we need to run k times to compare (ith time is to compare the position ith of each name, goes backward so from (k-1)th->0th), for each time, we use counting sort to sort the array, which takes O(n)
In conclusion, we will have O(nk) @cobalt sedge in fact, it would be O(nk*256) as inside the counting sort , u ll need to run through the characters to find position but as 256 is constant so just ignore it
Have a look here https://www.geeksforgeeks.org/radix-sort/

GeeksforGeeks

Radix Sort - GeeksforGeeks

A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions.

cobalt sedge Oct 24, 2020, 11:00 AM

#

thanks for ur help 🙂

#

Sorry for keep asking question, but I am really confused with this course...
So I want to ask, according to this question, is it mean that with the best solution is shortest job first? if thats the case, I think I can come up with an algorithm, but if not, I think it will be the big challenge for me again...

📎 Screenshot_2020-10-24_at_19.02.44.png

wispy sierra Oct 24, 2020, 11:31 AM

#

@cobalt sedge for your question, whether shortest job first is a No as ex: L = [5,3,1], P =[100,1,1], it 's gonna produce false result

fiery cosmos Oct 24, 2020, 11:44 AM

#

@cobalt sedge Hmm my gut says that you need to sort the array and then find the result

#

wait no I still need to consider priorities

#

ah so ig you need to sort based on the priorites

#

the one with the least priority should be kept at last

bronze sail Oct 24, 2020, 11:46 AM

#

@bronze sail I think it would depend on how complexity of your games. if there is no obstacles on the way then just simply calculate the angle between the swarm and the food the let the swarm head towards the food follow the calculated angle. if there is wall of any obstacles between then perhaps apply some path-finding algorithms (swarm is the starting point and food is destination)
@wispy sierra I was wondering actually how to implement just lifegame, should I store foods in list, or maybe in numyp array, but then it will not be constant 😛

fiery cosmos Oct 24, 2020, 11:47 AM

#

since the value of L increases from left to right

wispy sierra Oct 24, 2020, 11:49 AM

#

@fiery cosmos if sort by priority, it would fail for the example in the problem

#

for me, we ll sort based on value (P[i]/L[i]) (priority per unit), then yes greedy based on the sorted array 😛

#

@bronze sail my question is what u want your player to be? a swarm??

fiery cosmos Oct 24, 2020, 12:08 PM

#

I don't think it would fail for your test case

#

however I am trying to find one

#

Oh oops now I see the fault in mine

#

I am assuming P is the same for any order of processes

#

which is false

bronze sail Oct 24, 2020, 12:13 PM

#

@bronze sail my question is what u want your player to be? a swarm??
@wispy sierra not swarm, each should decide for its own where to go. I am using something set that stores position to check if they colide, lets say they are attracted to closest food

#

found it, i was inspired by this game https://youtu.be/-ujaymURIFo?t=92

YouTube

Petter Säterskog

Cell Lab

Promotional video for the Android simulation game Cell Lab: Evolution Sandbox.

Cell Lab is available for free in Google Play Store,
https://play.google.com/store/apps/details?id=com.saterskog.cell_lab

A forum to discuss the game is available at http://cell-lab.forumatic.com

▶ Play video

#

some bacis, food finding alorightm actually, that what I am looking for 😄

fiery cosmos Oct 24, 2020, 12:20 PM

#

What would be the answer according P[i] / L[i] sorting in this case?
L = [5, 3, 1] P = [1/6, 1/11, 1/2]

#

according to brute force solver the optimal sequence is (1, 2, 0)

wispy sierra Oct 24, 2020, 12:27 PM

#

mine one is (2,0,1) I think

fiery cosmos Oct 24, 2020, 12:30 PM

#

yes you are right

wispy sierra Oct 24, 2020, 12:30 PM

#

@bronze sail got no idea what the video is about! but it looks great except the bgm is terrible @@

fiery cosmos Oct 24, 2020, 12:30 PM

#

sort by P[i]/L[i]

#

gives correct

bronze sail Oct 24, 2020, 12:34 PM

#

bmg? @wispy sierra you just control params of that bacterias, so they eat and grow 😛 game of life simple

wispy sierra Oct 24, 2020, 12:35 PM

#

Oops,typo *bgm: background music 😛

#

@bronze sail you may want to start to code some draft version so we could see how could we improve the implementation lemon_smug

bronze sail Oct 24, 2020, 12:45 PM

#

si, I already got one, but im taking break

#

!paste

halcyon plankBOT Oct 24, 2020, 12:46 PM

#

Pasting large amounts of code

If your code is too long to fit in a codeblock in discord, you can paste your code here:
https://paste.pydis.com/

After pasting your code, save it by clicking the floppy disk icon in the top right, or by typing ctrl + S. After doing that, the URL should change. Copy the URL and post it here so others can see it.

bronze sail Oct 24, 2020, 12:47 PM

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@wispy sierra https://paste.pythondiscord.com/zapizahobo.rb, so for not it only spawn food and players, nothing is moving yet :d

#

nothing special yet 😄

📎 Screenshot_from_2020-10-24_14-47-45.png

cobalt sedge Oct 24, 2020, 1:11 PM

#

Thanks for all your help, so i need to sort it by P[i]/L[i] right?

fair prairie Oct 24, 2020, 3:15 PM

#

Hello, I can't understand the code of merge sort algo?anyone help me?

agile sundial Oct 24, 2020, 3:15 PM

#

which partt

fair prairie Oct 24, 2020, 3:16 PM

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Splitting up and merging up

#

The whole algo is based on it

agile sundial Oct 24, 2020, 3:17 PM

#

it is called merge sort after all

fair prairie Oct 24, 2020, 3:17 PM

#

Ya

fiery cosmos Oct 24, 2020, 3:22 PM

#

@fair prairie the splitting part is pretty easy did you understand it?

#

def merge_sort(arr):
    # if you have an array of length 1 it is already sorted
    if len(arr) == 1:
        return arr
    # else find the mid of the array
    mid = len(arr) // 2
    # sort the left part of the array
    left_sorted = merge_sort(arr[:mid])
    # sort the right part of the array
    right_sorted = merge_sort(arr[mid:])
    # now merge the left and right part by calling merge function
    sorted_arr = merge(arr[:mid], arr[mid:])
    return sorted_arr

#

now the merge function will look like this(not the shortest one)

def merge(left, right):
    # this will be populated and will be sorted
    merged_arr = []
    # i and j represent the start indices of left and right array
    i = j = 0
    # traverse both the list until one of them becomes empty
    while i < len(left) and j < len(right):
        # here the right array element is samller so append it
        if left[i] > right[j]:
            merged_arr.append(right[j])
            j += 1      # don't forget this
        else:    # the left array element is smaller so append it
            merged_arr.append(left[i])
            i += 1      # don't forget this
    # append the remaining elements of left array if any are left
    while i < len(left):
        merged_arr.append(left[i])
        i += 1          # don't forget this
    # append the remaining elements of right array if any are left
    while j < len(right):
        merged_arr.append(right[j])
        j += 1          # don't forget this
    # finally return the sorted merged array
    return merged_arr

fair prairie Oct 24, 2020, 4:36 PM

#

@(@fiery cosmos thx

cobalt sedge Oct 24, 2020, 7:04 PM

#

Sorry for keep asking question, but I am really confused with this course...
So I want to ask, according to this question, is it mean that with the best solution is shortest job first? if thats the case, I think I can come up with an algorithm, but if not, I think it will be the big challenge for me again...
@cobalt sedge

So can i do this?

#

📎 image0.png

wraith valve Oct 24, 2020, 7:45 PM

#

i think u need to call merge on both halves of the array and have something that appends the halves together at the end

#

or maybe thats what ur Mergesort line does

fiery cosmos Oct 25, 2020, 2:53 AM

#

Hey i have one dumb question,
So where does the learnt data of AI is stored??? is it database like SQL or some virtual memory and it changes every time device is changed???

wraith valve Oct 25, 2020, 3:12 AM

#

if ur talking about machine learning u can kind of think of it like doing regression for a function

#

basically when u "train" u tweek the parameters of ur function until u get ur desired accuracy

#

like u know when u had a bunch of data points and u had to find the line of best fit, thats kinda what machine learning is doing

fiery cosmos Oct 25, 2020, 4:35 AM

#

The data that is learnt is stored in form of sequences like NumPy arrays

fiery cosmos Oct 25, 2020, 5:05 AM

#

ahhh ok ok

#

so the learnt model data is transferable right?? we can use it on another models too right ?? or it wont work

fiery cosmos Oct 25, 2020, 5:33 AM

#

yes you can use it on other models

#

those are called pretrained models

#

where you utilise the already learnt parameters

fiery cosmos Oct 25, 2020, 6:40 AM

#

Awesome then :)

carmine kraken Oct 25, 2020, 7:08 AM

#

where is general guy?

#

i think lost

tender cairn Oct 25, 2020, 8:02 AM

#

Which is a good book to study DSA?

torn scarab Oct 25, 2020, 8:03 AM

#

https://runestone.academy/runestone/books/published/pythonds/index.html is a safe choice

Problem Solving with Algorithms and Data Structures using Python — ...

An interactive version of Problem Solving with Algorithms and Data Structures using Python.

tender cairn Oct 25, 2020, 8:09 AM

#

Thanks 🙂

fiery cosmos Oct 25, 2020, 9:05 AM

#

Also don't forget the CLRS textbook

agile sundial Oct 25, 2020, 1:38 PM

#

^ great book

torn scarab Oct 25, 2020, 2:42 PM

#

CLRS is pretty information dense, I wouldn't recommend it for starters. It's an awesome resource though, https://en.wikipedia.org/wiki/Introduction_to_Algorithms for context

agile sundial Oct 25, 2020, 2:51 PM

#

yeah, it's not meant for an introduction to programming

keen hearth Oct 25, 2020, 6:41 PM

#

Khan Academy actually has a great algorithms course for beginners. It's free and was put together with the help of Thomas Cormen -- who is the C in CLRS.

agile sundial Oct 25, 2020, 8:37 PM

#

it's in js, right?

lunar schooner Oct 25, 2020, 9:47 PM

#

yes

stray tusk Oct 25, 2020, 10:32 PM

#

Hey could someone help me with my selection sort function

agile sundial Oct 25, 2020, 10:32 PM

#

sure

#

!code could you use this

halcyon plankBOT Oct 25, 2020, 10:33 PM

#

Discord has support for Markdown, which allows you to post code with full syntax highlighting. Please use these whenever you paste code, as this helps improve the legibility and makes it easier for us to help you.

To do this, use the following method:

```python
print('Hello world!')
```

Note:
• These are backticks, not quotes. Backticks can usually be found on the tilde key.
• You can also use py as the language instead of python
• The language must be on the first line next to the backticks with no space between them

This will result in the following:

print('Hello world!')

stray tusk Oct 25, 2020, 10:34 PM

#

def selection_sort(alist):
    count = 0
    for i in range(len(alist) - 1, 0, -1):
        max_pos = 0
        count += 1
        for j in range(1, i + 1):
            count += 1
            if alist[j] > alist[max_pos]:
                count += 1
                max_pos = j
        count += 1
        temp = alist[i]
        alist[i] = alist[max_pos]
        alist[max_pos] = temp
    count += 1
    return count

#

so this is my function

#

and this is my tester function

#

    def test_01_selection(self):
        nums = [23, 10, 49, 12]
        comps = selection_sort(nums)
        self.assertEqual(comps, 6)
        self.assertEqual(nums, [10, 12, 23, 49])

agile sundial Oct 25, 2020, 10:35 PM

#

what issue are you having?

stray tusk Oct 25, 2020, 10:39 PM

#

first, im supposed to have . Expected: 14 but my Actual is 6

kindred flame Oct 26, 2020, 1:41 AM

#

hey guys is anyone good with using bfs or Breadth-First Search for binary search treea

oblique panther Oct 26, 2020, 1:45 AM

#

@kindred flame what code have you written so far?

kindred flame Oct 26, 2020, 1:45 AM

#

just bunch of random tries

oblique panther Oct 26, 2020, 1:45 AM

#

can you tell me in your own words what a breadth first search is?

kindred flame Oct 26, 2020, 1:45 AM

#

def bfs(self, node: Node) -> Generator[Node, None, None]:
"""
Insert Docstring here
"""
q = queue.Queue()

    if node is None:
        return
    while not q.empty():
        yield q.get()
    print(node, ",")
    yield node




    for n in RBtree.bfs(self, node.left):
        q.put(node.right)
        yield n





    #for n in RBtree.bfs(self, RBtree.get_sibling(node)):
        #yield n
        #print(node, ",")



    #if RBtree.get_sibling(node) != None and RBtree.get_sibling(node).value == node.parent.right.value:
     #   yield RBtree.get_sibling(node.left)
      #  print(RBtree.get_sibling(node), ",")

    #yield RBtree.bfs(self, node.left)

oblique panther Oct 26, 2020, 1:46 AM

#

try using markdown and not having so many blank lines

#

```py
code
```

wraith valve Oct 26, 2020, 1:47 AM

#

y r u using a generator in a breadth first search

oblique panther Oct 26, 2020, 1:47 AM

#

@wraith valve it's a good idea, actually

wraith valve Oct 26, 2020, 1:47 AM

#

like u can just enqueue and dequeue to keep it simple

oblique panther Oct 26, 2020, 1:47 AM

#

a generator is simple

kindred flame Oct 26, 2020, 1:47 AM

#

alright lets say I have a tree like this

                  14 (root node)
       7                        21

3 10 17 25

as I understood it, we devide that input layer by layer so 1st level is 14 then 2nd is 7, 21 and third is 3,10,17,25

#

so it will output something like bfs = [14, 7, 21, 3, 10, 17, 25]

#

can we do it without the queue ?

oblique panther Oct 26, 2020, 1:48 AM

#

I would use a queue

kindred flame Oct 26, 2020, 1:49 AM

#

how tho

oblique panther Oct 26, 2020, 1:49 AM

#

is there a reason you don't want to use one?

kindred flame Oct 26, 2020, 1:49 AM

#

becuase not sure how to exactly use it

#

I was watching a vid using it

oblique panther Oct 26, 2020, 1:49 AM

#

the queue would be for storing nodes that you haven't visited yet

kindred flame Oct 26, 2020, 1:49 AM

#

but when i try it my code freeze

oblique panther Oct 26, 2020, 1:49 AM

#

adding a node to the queue isn't the same as visiting it

kindred flame Oct 26, 2020, 1:50 AM

#

can we add object types to queue ?

oblique panther Oct 26, 2020, 1:50 AM

#

~~you can add any object to a queue, and types are objects~~ <- this is a true statement that you can ignore

#

are you asking if you can add Node instances to a queue?

kindred flame Oct 26, 2020, 1:50 AM

#

yeah

#

so if i can add it how can i make it work then

#

so first of all is this first bit correct

#

q = queue.Queue()
if node is None:
return

#

I am defining my queue

oblique panther Oct 26, 2020, 1:51 AM

#

did you implement a queue class yourself?

kindred flame Oct 26, 2020, 1:51 AM

#

and then if we dont have any nodes anymore we stop yielding right ?

oblique panther Oct 26, 2020, 1:51 AM

#

because there's one in the standard library

kindred flame Oct 26, 2020, 1:51 AM

#

no I just have import queue

oblique panther Oct 26, 2020, 1:52 AM

#

oh okay

#

I don't know the names of the methods for that

#

anyway

#algos-and-data-structs

Cases: (1) insert into empty list, (2) insert before the head, (3) insert in the interior

Make a 5x5 array filled with 1's with column names of 'a','b','c','d','e', and types of 32 bit int; do this on only 1 line of code

The output will look like this: [(1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1) (1, 1, 1, 1, 1)]

Change every value in it that is not on the edge of a zero; do this on only 1 line of code

The output will look like this: [(1, 1, 1, 1, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 0, 0, 0, 1) (1, 1, 1, 1, 1)]

Create a second view of the first view that shows only the middle 9 places; do this on only 1 line of code

The output of the 2nd view will look like this: [(1, 0, 1) (1, 0, 1) (1, 0, 1)]