algos-and-data-structs

[rich ridge]

    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None
def maxDepth(node):
    if node is None:
        return 0
    else:
        return max(maxDepth(node.left),maxDepth(node.right)) + 1

root = Node(5)
root.left = Node(6)
root.right = Node(7)
root.left.left = Node(8)
root.left.right = Node(9)
print("Height of tree is %d" %(maxDepth(root)))

How do we calculate ht of binary tree when there is no incremental counting in above program ??

[rich ridge]

answer is 3

[fiery cosmos]

Hey can someone help me with a deepdream neural network? I have my own dataset I want to train it with

[vocal gorge]

There it is:
return max(maxDepth(node.left),maxDepth(node.right)) + 1

[floral crane]

Can someone please explain the qiucksort to me

[north zealot]

Hey @next storm, please do not post random memes in the server

[north zealot]

!mute @next storm 5h Posting a meme just after a mod ask you not to isn't the way to go. Please re-read over our #rules.

[halcyon plank]

:incoming_envelope: :ok_hand: applied mute to @next storm until 2021-02-02 16:09 (4 hours and 59 minutes).

[wispy hare]

you can directly ask

[wispy hare]

by the way define your class Node as:

    def __init__(self, data=None, left=None, right=None):
        self.data = data
        self.left = left
        self.right = right```
it gives you the ability to create a tree like this `tree = Node(5, Node(6, Node(8), Node(9)), Node(7))` for example

[eager hamlet]

given a list of points and another point, how would i efficiently check whether the manhattan distance between any of them and the other point is less than or equal to n?

(ping 2 reply thx)

[buoyant badger]

how do i ask directly ?

[eager hamlet]

you just ask your questoin lol

[buoyant badger]

lol

[eager hamlet]

ok uh

ok so i found out

i found a better problem to solve that would solve my problem

given a grid of points labelled either A or B, is there a way to calculate the closest B point to each A point (through manhattan distance)?

[buoyant prawn]

Guys any good course to learn algos and data structure ?

[buoyant badger]

how do i get all permutations of [-,+,*]

idk how to work with 3

[wicked coyote]

just brute force ig?

srry could u elaborate on the question?

I need more info to provide a good answer

[lean dome]

check out itertools.permutations.

!e ```py
import itertools
print(list(itertools.permutations("-+*")))

[halcyon plank]

@lean dome :white_check_mark: Your eval job has completed with return code 0.

[('-', '+', '*'), ('-', '*', '+'), ('+', '-', '*'), ('+', '*', '-'), ('*', '-', '+'), ('*', '+', '-')]

[buoyant badger]

i kinda cant use that i need to use recursion

since i need to find all expression that give that target

nums = [1, 2, 3] and target = 6 → 2 (expressions: 1 + 2 + 3, 1 * 2 * 3) *example

[vocal gorge]

To get all permutations of n things, separate out the first thing (we'll call it A), and get all permutations of the remaining n-1 things. Then, for each such permutation, generate n new permutations, corresponding to the n different places you can insert A in.

For example, for 1,2,3. All permutations of 2,3 are [2,3], [3,2]. Insert 1 into 3 possible positions in each:

[2,3] -> [1,2,3], [2,1,3], [2,3,1]
[3,2] -> [1,3,2], [3,1,2], [3,2,1]

So you get 6 permutations of 1,2,3, as you should.

That's your recursive algorithm.

[fiery cosmos]

Take Developer Ecosystem Survey by JetBrains
https://t.co/S8US6FsJAQ?amp=1

[fiery cosmos]

hey guys! how would i go about implementing a sorting algorithm for example quicksort in a way that i can store its state and resume sorting later? or should i just use a sorting algo without recursion? i looked into external sorting but its not exactly what im looking for

[flat sorrel]

Not entirely sure what you mean but perhaps create a wrapper class around a list that overrides mutator methods so that they "pause" the algorithm somehow?

[balmy oak]

@fiery cosmos Perhaps you can do that with generators

[fiery cosmos]

thx ill look into that

[stable pecan]

it is possible

[brazen imp]

guys could anyone help me in exam

it will be start in 3mins

dm me

if u want to help

[lucid whale]

[wicked coyote]

https://codeforces.com/contest/1387/problem/A

Could you solve this my first making the black edge 0 and the red edge 1. Then you solve it but make it so u start with either 0 or 1 in the node. Then after that u add .5 to every single node that way black edge becomes 1 and red edge becomes 2. But how would you prove / disprove the fact that u could solve red edge 1 and black edge 0 with starting 0 or 1 in initial node?

[vocal gorge]

Just a tree? There's also the term p-ary tree for trees with p children per node.

[subtle hearth]

the non-euclidean distance is what you want to google

basically, just think about moving only on the x or y direction but not both at the same time, how would you get somewhere without using diagonal (sloped) paths

Like you would in Manhattan

Is this aoc?

[eager hamlet]

no

it's usaco

[rustic hatch]

hi, could someone help me determine the complexity of an algorithm?

https://colab.research.google.com/drive/1k_MvIY0n7NYM-k2x8nob-CVuh2ymgUfL?usp=sharing

[subtle hearth]

what is the distance from (0, 5) on a graph to (0, 0) on a graph?

[eager hamlet]

5

[subtle hearth]

right and same with (0, -5)

[eager hamlet]

uh yeah

[subtle hearth]

now (1, -5) is 6 away from (0, 0) because you also have to go down 1

right 5, down 1

so just check the distance from each point to every other point

and pair the distance with the coordinate in some data structure like a list of tuples or soemthing

[vocal gorge]

You mean, like, in less than O(n*m)?

[eager hamlet]

yeah

just pure linear

max a mil points so

[subtle hearth]

Ahh that may take a while with my naive method haha

[vocal gorge]

no idea, I'd want to know too. There are spacial subdivision algoritmhs for that, but I don't know an implementation

by the way, the good way to calculate the naive way would be with the holy grail: scipy.spatial.distance.cdist

https://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.distance.cdist.html#scipy.spatial.distance.cdist
for example,

dists = cdist(As,Bs,"cityblock")

for cityblock distance

then do argmin to find the closest B for each A.

[subtle hearth]

Ohh that's handy, what do you mean by argmin?

[vocal gorge]

np.argmin

[subtle hearth]

ahhh

[vocal gorge]

can do things like "for each row, get the index of the lowest column in that row"

[subtle hearth]

I think I need to understand np arrays better to get what you are talking about

[vocal gorge]

the ith row in the array returned by cdist will be the distances from As[i] to each of the Bs.

so to find the closest B-point, you need the minimum in the row. But not the minimum's value, but its index - hence, argmin and not min.

[subtle hearth]

Euclidean Algorithm to find the GCD of two numbers: Voila py def euclidean_algorithm(nums): if all(nums): greater = max(nums) smaller = min(nums) remainder = greater % smaller if remainder == 0: return smaller else: return euclidean_algorithm((smaller, remainder)) else: return max(nums) numbers = 0, 5465465654654654 print(euclidean_algorithm(numbers)) slaps hood

[agile sundial]

nums is a tuple, you don't need to unpack it into a list

or unpack it into max

[subtle hearth]

Can I just put nums into all() like ```py
all(nums)

Niiice

[agile sundial]

yep, nums is a tuple

[subtle hearth]

fixed

thanks!

[fair latch]

how much python should you know before jumping into data structures/algo problems?

[crimson wave]

can i get any fake profile detection projects

[fiery cosmos]

Any YouTube playlist for Graphs, Binary Tree and advanced data structures!!

[feral flint]

ע

[keen hearth]

I mean, really you can study algorithms without knowing any programming language. But it can be helpful to be able to implement the algorithm yourself.

Studying algorithms goes hand-in-hand with learning Python, as python has some useful data-structures built-in.

set and dict are hash-tables; list is a dynamic-array; sorted implements a hybrid of merge-sort and insertion-sort (called Tim-sort)

[green cobalt]

will u help me with 0(1) space complexity?
what it is

??

[trim fiber]

O(1) is when you always do finite number of steps for every input

For example if you are iterating through array it's not O(1) because different arrays have different number of elements

[keen hearth]

It's where the additional memory required by an algorithm to run does not depend on the size of the input.

This is also known as an in-place algorithm.

Check out the table of sorting algorithms here. Ones with 1 in the "Memory" column are in-place: https://en.wikipedia.org/wiki/Sorting_algorithm#Comparison_of_algorithms

Another example: take the problem of reversing a list. You could create a new list, and insert the elements into that list in reversed order; this would not be in-place. Or, you could work from the outside in, swapping corresponding pairs of elements; this would be in-place.

def reverse(arr):
    new_arr = []
    i = len(arr) - 1
    while i >= 0:
        new_arr.append(arr[i])
        i -= 1
    return new_arr

def in_place_reverse(arr):
    i, j = 0, len(arr) - 1
    while i < j:
        arr[i], arr[j] = arr[j], arr[i]
        i += 1
        j -= 1

[worthy rivet]

hello everyone,I'm new to this server and in my first year of b tech...i am stuck in a problem can anyone point out my mistake in it.it would be really helpful🥺 .....question link:https://www.codechef.com/problems/INTRVS

[steady arch]

hmm ill try solving it

and maybe helping u out

but im in tenth grade so im not sure whether ill be able to

but ill try

just gimme some time

ooh the first problem i think i can see is that u didnt unpack the list containing the input('').split() that u used

to take the n and k integers

as input

[raw bridge]

does iterative solutions have better space complexity than recursive ones on an average scale?

[mint jewel]

generally yes

but it is not a hard rule

[raw bridge]

ah

[ruby swan]

Bot should be displayed if he has solve the problems in "at most one second each". In your code you check for at most 'K' seconds.

[worthy rivet]

thank you...i found that....ps too silly though

[fair latch]

So right now I'm taking an intro to Python course. Yes, I'm learning about abstract data types/structures - but not quite implementing anything. I'm learning a lot, but I feel like I want to jump into DS/Algos already and I'm wasting time. At the same time, I feel like I don't know enough about python to understand the implementation of data structures.

[keen hearth]

Python probably isn't the best language to practice implementing data structures, as it's so high-level. Perhaps something like Java or C++ would be better suited.

Implementing can help you to really understand a data-structure, but it's also important to know when to use it. Practicing programming problems on sites like leetcode or hackerrank can help with this. You don't need to know a lot of python for the easy/medium problems, and it's ok to attempt a problem and look at model solutions if you aren't able to solve it.

[fair latch]

My dilemma is that I know a little about a few different programming languages: Java, Python, & JavaScript. My favorite is Java and would love to learn DS using Java, but I'm also a Data Science/SWE student, and the language that makes the most sense to make my "native" language is Python. I have tried some of the easy problems on Leetcode, and struggled a lot, so that's why I'm going back to build my Python knowledge before attempting any problems.

[maiden hornet]

Binary Tree Question given an array POSTORDER[n] and PREORDER[n] and variable i, j ... how can i determine if i is a parent of j using the 2 arrays?

[flint mason]

wheres a good place to start.

[modest pecan]

When i have a JSON Like this:

my_dictionary = {
    "key 1": "Value 1",
    "key 2": "Value 2",
    "decimal": 100,
    "boolean": False,
    "list": [1, 2, 3],
    "dict": {
        "child key 1": "value 1",
        "child key 2": "value 2"
    }
}

How can i get the value from child key 1?

[fresh moss]

my_dictionary[“dict”][“child key 1”]

Or my_dictionary.get(“dict”, {}).get(“child key 1”) if you want to be safe

[rough osprey]

not completely safe:

d = {'key': None}
d.get('key', {}).get('some')

[halcyon plank]

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

[fiery cosmos]

hey guys

re.match(r"[0-9][0-9]okt$|[0-9][0-9]maj$|[0-9][0-9]febr$", "adsf18majadsf")

returns None but i want it to match on 2 numbers followed by a "febr" or a "maj" or an "okt"
how could i achieve this? thanks in advance :)

[brave oak]

🥴

r'\d{2}(febr|maj|okt)'

[fiery cosmos]

i know im pretty new to regex

[brave oak]

can you explain

the multiple $s

[fiery cosmos]

i've solved it since then

but thanks :)

[brave oak]

yw

lmk if you need explanations

[fiery cosmos]

thanks :)

[final egret]

really simply question ... I don't know how to use a function within a class...

class Solution:
def combinationSum(self, candidates, target):
self.res = []
self.candidates = candidates
self.backtrack([],self.target,0) #start at 0th index
return self.res
def backtrack(self,path,target,idx):
if target == 0:
self.res.append(path)
return
if target <0:
return
for x in range(idx,len(self.candidates)):
self.backtrack(path + [self.candidates[x]], target - [self.candidates[x]])
target - [self.candidates[x]]

why doesn't doing

Solution(candidates,target) ... how can i run the function combinationSum in this class?

[spring grove]

in order to run functions inside of a class you first have to create an instance of that class and then use the function.

[autumn whale]

you need to declare a constructor for the class

[spring grove]

^and that

try looking at using __init__ as a constructor

what is it youre trying to do @final egret ?

[compact cloud]

yo are there people that can help with competitve programming questions?

https://dmoj.ca/problem/ccc16s3

[subtle hearth]

Generated 10,000,002 points of y=sqrt(1**2 + x**2)
Quadrants copied, new points: 40,000,008 points of y=sqrt(1**2 + x**2)
true pi........ 3.141592653589793
as generated... 3.141592653580496
corrected...... 3.14159265358
``` How could I make this more accurate? https://pastebin.com/VXiZEPc8

[vocal gorge]

y=sqrt(1**2 + x**2)
Presumably, you mean - 🙂

And I don't think you can get more accuracy than that using floats. You'd have to switch to Decimal.

(it's not the current value to full float precision, but I wasn't able to improve it)

[subtle hearth]

Ahh typo! Ok, maybe I will look more into an advanced way to do it then!

[vocal gorge]

looks like there's a problem with using decimals

from decimal import Decimal as D
import decimal
decimal.getcontext().prec=28
def pi_est_dec(N):
    step = D(2)/(N-1)
    stepsq = step**2
    total = D(0)
    cur_x = D(-1)+step
    last_y = 0
    for i in range(1,N):
        cur_y = (1-cur_x**2).sqrt()
        total += ((cur_y-last_y)**2 + stepsq).sqrt()
        last_y = cur_y
        cur_x += step
    return total
print(pi_est_dec(1000000))
print("3.1415926535897932384626433832795029") # true 35 digits from wolfram

Output:

3.141592652756257066384470676
3.1415926535897932384626433832795029

This takes around 10 seconds already. So Decimals can achieve higher accuracy than floats... but for that you still need to have enough points.

And decimals are far slower, so it's hard to get that many points.

[subtle hearth]

Hmm yeah doesn't seem to be that effective... I can get that accuracy but it only takes 2-3 seconds for 1 mil iterations. What exactly does decimal do? Guessing it's for use with currency and very small important numbers

Oh does it store the decimal as an int or soemthing?

[vocal gorge]

Python floats are the same as numpy's float64, and the same that's called "double"s in other languages - 64bit floating-point numbers. They are implemented in hardware, that's what modern CPUs are build to work with. If you need more precision than that, the only way is to implement such numbers in software. That's what the decimal library does. Of course, doing in software what's usually done in hardware is way, way slower.

In general, that's what's is known as "arbitrary-precision arithmetic". It's when you implement your own numbers in software so that you can get as much precision as you need.

[subtle hearth]

Rocket science, Finance, and finding the value of pi, thx arbitrary precision arithmetic!

[vocal gorge]

yeah, another use of decimals is that they aren't floats

like, they are fixed-point and not floating-point

in anything money-related you want fixed-point numbers, everywhere - not for precision, just for the lack of loss of precision in intermediate calculations

you don't want 10 cent + 10 cent +... + 10 cent (10 times) to be equal to 0.999999999 dollars.

[subtle hearth]

Right or like when ur trying to do the Pythagorean theorem 10,000,00 times haha

[fiery cosmos]

hello

oh

[copper arrow]

Hey its been a while

[lyric bramble]

Given an array of size n, find the majority element. The majority element is the element that appears more than floor(n/2) times.

You may assume that the array is non-empty and the majority element always exist in the array.

Example :

Input : [2, 1, 2]
Return : 2 which occurs 2 times which is greater than 3/2.

what could be the best time complexity for this

[vocal gorge]

Time complexity? O(n), pretty clearly, as it's achievable and I don't think it's possible to do less.
(to achieve, make a Counter, then pick the element with the most appearances)

[main flower]

Yeah, O(n) seems the best the best

Altough, you are probably going to use a hash table for a counter

So you should watch out for hash collisions

cuz then it could be O(n^2)

[vocal gorge]

Does anyone actually expect hash collision problems in real applications? I got the impression that they only really happen (in large amounts) when you manually design a hash function that's very bad.

[main flower]

Well, I'm not sure, but they can happen so It's better to watch out

Another thing would be to just sort the array

In O(nlogn)

And then just acces mid+1-th element

I mean, for arrays with even number of elements acces n/2-th element while for arrays with odd num of elements access n/2+1-th element

[soft sequoia]

I have a test, the questions will be based on algorithm, data structure such,,, how should I prepare for it??? Any help is appreciated thank you :)

[tame wigeon]

Try your best to solve as many questions as you can related to the materials, preferably on your own. Try to learn the pattern then apply it to questions on the test.

Use geekforgeeks website if it consists pseudo code or any implementation.

Hackerrank.com is also good for a long run I don't recommend it for a test though

[undone ingot]

How can I define a function where you don’t have to put all arguments when you execute it?

[soft sequoia]

@tame wigeon thank you!

[lucid olive]

ay u know any good resources to learn data structures and algos for beginners

preferably free

[rustic portal]

I'm doing coding challange and I think my issues is not undertanding how to apply algo's to solutions, is there a good website or video to increase my undertanding?

[bleak tapir]

@undone ingot
https://book.pythontips.com/en/latest/args_and_kwargs.html

also wrong channel, ask in #python-discussion if simple stuff

[eager hamlet]

idk, the only thing i can suggest is just grind problems

[uneven jungle]

@rustic portal go check this book: Data Structures and Algorithms in Python, Michael T. Goodrich. It exists in pdf version., it's really great.

[floral crane]

What is quicksory

[agile sundial]

quicksort?

[fiery cosmos]

hi

I try to use variable and definitions external to the file, but can't find a way to do it.

example:
test1.py:

def a():
    return 1;

test2.py:

def b():
    result = b.test;
    result = 1 + a();
    return result

main.py:

import test1, test2
client = "test";
print(b());

I know you can but I have no idea how.

[spring grove]

if the file is in the same directory you can use:

from test1 import a
from test2 import b
print(b())

if you use your method then:

import test1
import test2
print(test2.b())

@fiery cosmos

[fair plover]

This is kind of a more general quesstion but should you include floor/ceilings in timee complexity?

Like if an algorithm has floor(n) times, should it be O(n) or O(floor(n))

[fiery cosmos]

@spring grove thk

what can i do if i need to use a variable from the running file?

test.py:

def a():
    print(client)

run.py:

import test
client = "hi"
a()

since it tells me that client is not defined.

[spring grove]

You should probably just make your function return that variable

[fiery cosmos]

yes, but the variable is not defined.

[spring grove]

@fiery cosmos or make your function take a parameter

def a(thing_i_want_to_print):
  print(thing_i_want_to_print)

then
import test
test.a('hi')

@fiery cosmos if you dont want to use either of those mthods, make your variable global and pass it to the next file

its better practice to use either of the first 2

[fiery cosmos]

yes

[rich cairn]

hey guys idk if this is the right channel

couldnt find a channel for matplotlib.pyplot

so im asking here, how do i solve this?

[rich cairn]

y=np.array([2,3,4,5,6,7])
plt.scatter(x,y,color='red')
plt.show()```

this is it?

[vocal gorge]

How exactly do you expect someone to answer the question "how do I solve this", without having given any details on, well, what you're trying to do?

[vocal gorge]

there isn't one, but a help channel(#❓｜how-to-get-help) would do

[flat sorrel]

Since matplotlib is commonly used in data science projects, asking in #data-science-and-ml would be appropriate.

Btw you could always just run your code to verify that it's correct

[rich cairn]

epic thanks

[rich cairn]

yes lol i got it later, nvm me.

[fiery cosmos]

can someone convert .py to exe for me

[coral loom]

When defining dictionaries in Python, how would I store the first element of every grouped tuple list just as a dictionary key?

[mint jewel]

what do you want as the values?

[coral loom]

At the moment when I create my dictionary using a for-loop over the list of tuples, I get the following output (which still includes tuples):

You can see, there's a comma separating each name-value pairs but within each **name ** you might have noticed there's additional ** two element **enclosed with a pair of parenthesis (a tuple otherwise known as)

[mint jewel]

well, you would do ```py
{first: value for fist, *rest in some_list_of_tuples}

[coral loom]

Wait what? Hold on, let me show you how I currently done my dictionary...

[mint jewel]

ah

[coral loom]

named_entities is the list with tuples

ne_dict is the Named Entity dictionary

[mint jewel]

so the second elements are entirely irrelevant here?

[coral loom]

For my purpose in this particular count_entity_freq_dict function, yes it is irrelevant

[mint jewel]

on an unrelated note, I would suggest pprint so that the output is more readable

from collections import Counter
from pprint import pprint
pprint(dict(Counter(i[0] for i in named_entities)))

use Counter to count things

[coral loom]

So what I've done with my for-loop, you can easily do it with 1 liner? 😯

[mint jewel]

ye, counting things is so common that there is a helper class for it

[coral loom]

I can easily store this as a variable: dict(Counter(i[0] for i in named_entities)) right? And then pass the reference to pprint ( ) ...?

[mint jewel]

yes

[coral loom]

Thanks for your help lakmatiol 🙂

[pure marlin]

Hi guys I have problem with updating my JSON file.

for file in os.listdir("./python_files"):
    if file.endswith(".xlsx"):
        df = pd.read_excel(os.path.join("./python_files", file)) 
        CRD_Array = df.iloc[:,1].values
        column_length = len(CRD_Array)
        row_iterator = 0
        for single_CRD in CRD_Array: 
                    if os.path.isfile(f'output/{single_CRD}.json'):
                        with open(f"output/{single_CRD}.json", "r+") as json_file:
                            parsed_file = json.load(json_file)                     
                            parsed_file['body-{}'.format(file)]=[]
                            parsed_file['body-{}'.format(file)].append({
                              'Total Employees':  '{}'.format(filed_handler(df,row_iterator,'5A'))})
                            json.dump(parsed_file, json_file)```

When file is found I want to add new array to it

At this moment file isn't updated with new array

[compact otter]

Hey guys. I'm using weight of evidence to bin my continuous variables. Now that i have all weights, I want to replace my values by there WoE based on the bin they fall into. Is is possible to do this without using 10 if loops?

[flat sorrel]

values = []  # Your values
bins = []  # Populate this such that bins[i] is the bin index for values[i]
replacements = []  # Populate this such that replacement[i] is the replacement value for bin index i

for i, bin in enumerate(bins):
    values[i] = replacements[bin]

If your bins are named then bins would instead be a list of strings and replacements a dictionary

[lavish flame]

Hi I wanted to get started with Data structures and algo I am okay with lists dictionaries tuples arrays..is there any other pre-requisite before I start with it. It would be great if u could suggest a few sites where I can start as well

[latent wasp]

Hi,

I am looking to convert an integer from an integer to the following string:

Say we have a variable that holds the integer 240555
I want to convert it to the following string: "$240.6K"

How would I do that?

[lavish flame]

s="$"+str(round(float(num/1000),1))+"K", this will convert to K alsways

*always

[latent wasp]

hmm

let me see

[latent wasp]

wow it works!

thanks a lot @lavish flame

[fiery cosmos]

heyyy

[jovial hill]

Hi there, I would like to store a list of strings and I would like to add another string to the list only if the string is not present in the list. So for example if I have a list with ['the','blue'] and i want to add 'red' to the list, it will check if 'red' is present in the list. Since, it is not present in this case, it will add 'red' to the list. I would like to know if lists work best for this?

[spring grove]

hi @jovial hill maybe look at sets

you dont need to check if the item already exists, as duplicate entries cannot exist in a set

[jovial hill]

Aha, cheers 😋

[spring grove]

@jovial hill here 🙂 https://www.w3schools.com/python/python_sets.asp

[hallow vortex]

Hi guys, hope you are doing well. I was solving this LC, but I don't understand this solution. Could you please explain how this works?

it is LC 137 and its link is here: https://leetcode.com/problems/single-number-ii/

[zealous junco]

can anyone help to convert this code to javascript

class Solution:
def solve(self, n):
temp = str(n)
ans = float('-inf')
for i in range(len(temp) + 1):
cand = temp[:i] + '5' + temp[i:]
if i == 0 and temp[0] == '-':
continue
ans = max(ans, int(cand))
return ans
ob = Solution()
print(ob.solve(268))

[teal lake]

Hi

need helo

help

I need the function to add plurals

I had to create 2 lists becuase I couldnt figure it out

[jovial hill]

Wat do you mean by add plurals?

[clear urchin]

Hi !
I just want to know if there is a solution for this :

a = 4
type(a) #It return "int"
hex(a) #But hex(a) return "0x4" and i want that return "0x04"

[clear urchin]

Thank you @lavish flame

[lavish flame]

np I also learned something new!

[jovial hill]

I am crawling a website and I don't want to visit the same link more than once. To do this I would like to store the links_yet_to_visit in a queue and all the links either in the queue or have already been visited in a set. Each url will have its corresponding parameters and whether its a post or get request. How would I store the values in the queue and set. so each url with be something like:
[url1:{name1:value, name2:value}, post] [url2:{name1:value}, get] [url3:{name1:value, name2:value, name3:value, name4:value}, post]

I've gone for the following:
urls = {url1, url2, url3} left_to_visit = deque([[url1, {name1:value, name2:value}, post], [url2, {name1:value}, get] ]) visited_urls = [[url3, {name1:value, name2:value, name3:value, name4:value}, post ]]

So when I find a url, I check if its present in urls, if it isn't I append to urls and I append to left_to_visit. When I visit a url, I pop it from left_to_visit and store it in visted_urls

[fiery cosmos]

Hello, I need help with a python program. The goal of the program is to give a match list (to make a tournament) according to the number of teams. Except I don't have a clue how to do it, could you help me?

[clear urchin]

Bonjour,

first, if u want to specify all teams, you should find a way to initialize them with variables or list...

[fiery cosmos]

i don't need to specify them just number , i use a list

[clear urchin]

so you want to show something like : l[1] vs l[2] ?

[fiery cosmos]

yeah

[clear urchin]

so u can use something like this @fiery cosmos i think :

I guess every "equipe" is affected to a number.
Ex: Equipe 1 is affected to number 1, etc....

import random

opposant1 = 0
opposant2 = 0
for n in range(Match-1): #You will print as much many times as necessary
    while (opposant1 == opposant2):
        """
        you don't want that a team face himself lol.
        So you will run "random.randint(a,b)" until opposant1 and 2 are different.
        """
        opposant1 = l[random.randint(a,b)] #You define the minimum 'a' and maximum 'b' amount of teams.
        opposant2 = l[random.randint(a,b)]
    del opposant1 #You want to suppress teams that got a game.
    del opposant2
    print(opposant1+"vs"+opposant2) #Finally, you print the game.   

I'm not sure that it will work perfectly but i think that's the idea and i didn't think if we can dodge the utilization of the "while" loop. So it's not an optimized python script.

[agile sundial]

pretty sure that will not work

although, i'm not sure what you mean by "make a tournament", could you clarify? @fiery cosmos

[fiery cosmos]

@agile sundial for sure , the program serves after entering a number, to know all possible matches between them? (as an example if in a tournament there are 14 people) the program gives us the list for everyone to face everyone like this with 4 teams

[agile sundial]

i see

[agile sundial]

uh

[gloomy harbor]

anyone know how to work this out?

[vocal gorge]

well, that if is O(1), so just consider how many iterations is being done.

[clear urchin]

iterations or operations ? i think time complexity is about operations no ?
iterations is about space complexity ?

[agile sundial]

maybe

in this case he doesn't care about the space though

[vocal gorge]

Uhh, "iterations is about space complexity" is a very weird statement (how are iterations related to memory?), but also, here each iteration is a single operation, so you just need the number of iterations.

"iteration" just means "one execution of a loop".

[clear urchin]

my bad about space complexity HAHAH

i'm so n00b XD

[gloomy harbor]

so what is the time complexity then im still lost sorry

just O(1)?

[vocal gorge]

Uhh, no?

for i in range(n):
    some_operation_that_takes_constant_time(i)

what'd be the time complexity here?

[gloomy harbor]

erm im not sure tbh sorry

[vocal gorge]

How many times is some_operation_that_takes_constant_time called?

[gloomy harbor]

is O(n) i think

thats all I have to answer

in that ss

[vocal gorge]

^

[lean glade]

You can solve that by just doing:```python
import itertools

x = int(input("Amount of teams: "))
matches = itertools.combinations([i for i in range(1, x+1)], 2)

for match in matches:
print("/".join((str(i) for i in match)))```

[vocal gorge]

I think combinations accepts iterators as well as lists.

[lean glade]

Yeah ik

There, changed it for your liking

[vocal gorge]

also, that's technically only the first round of a tournament 😉

...but nevermind, the rest of the lines are not exactly important

[lean glade]

And also idk if the teacher wanted tillmister to do the whole process of selecting the different pairs for the matches

[pure terrace]

How can I define a method that accepts a variable number of paramaters? For instance, i have the following:

await self.add(member, action)

But on some occasions I want to add another variable:

await self.add(member, action, number)

and use number whenever is provided

[lean glade]

def func(*args):

Or you can use keyword arguments

[pure terrace]

I can also set a default value so that whenever is different to the default value is because there is value provided

[lean glade]

Yep, def func(member, action, number = None)

[pure terrace]

exactly, ty very much

[odd hill]

Hello! im getting this error

ERROR::CTag::init::Given souptag is not a bs4.element.Tag instance.

DEFAULT_LINK_ATTR_NAME ="href"
ODDSCHECKER_HOME = "https://www.oddschecker.com/"

Why dosent it work?:)

i already pip installed everything

[fossil topaz]

Hey, I have a question about an exams questions about bubble sort. It's more CS in general than Python-specific but I couldn't solve it right anyway.

This exercise (sorry for the Greek) wants me to "print" the array for every iteration of the bubble sort.

The original array A is [55, 34, 5, 2, 2, 1]

But the given solutions for this are very strange

For some reason, 1 which is at [-1], is being swapped to [0]

Can someone explain why that happens

def bubble_sort(arr):
    N = len(arr)
    for i in range(N):
        for j in range(N - 1, 0, -1):
            if arr[j] < arr[j - 1]:
                arr[j-1], arr[j] = arr[j], arr[j-1]

bubble_sort([55, 34, 5, 2, 2, 1])

[agile sundial]

it's swapping the min to the left instead of the max to the right

[fossil topaz]

yes that's what I thought

but the textbook actually gave me this code snippet

[agile sundial]

and?

[fossil topaz]

how should I do it

[agile sundial]

do what

[fossil topaz]

how should I implement a python function that would modify the array according to the needs of the exercise

sorry for the lack of clarity in my questions

[agile sundial]

that snippet already does what you need

[fossil topaz]

yes it gives the same result but the process is different

The exercise requires the first iteration to be [1, 55, 34, 5, 2, 2]

The textbook snippet does this: [55, 34, 5, 2, 1, 2]

[agile sundial]

i don't think so

maybe you're printing on every iteration of the inner loop instead of the outer loop

[fossil topaz]

No, I am not printing, I am using PythonTutor

It just visualises the executions

[agile sundial]

i see

the instructions say to print on each iteration

but you're looking at the result of each iteration of the inner loop

[fossil topaz]

so I need to print the iterations on the outer loop?

[agile sundial]

i think so

[fossil topaz]

yes you were right, a few frames ahead it actually shows the right thing

thank you

[dim cypress]

is anyone familiar with the Max^n (similar to minimax but for n players instead of 2)? I've been trying to implement the shallow pruning version of it for 2 days now using this paper:
https://www.cc.gatech.edu/~thad/6601-gradAI-fall2015/Korf_Multi-player-Alpha-beta-Pruning.pdf (specifically top of page 5)
but it's not working

[jovial tartan]

this might be an extremely stupid question but

when you have a function that includes a binary search (complexity is O(logN)) as well as a loop with complexity O(N) , then the complexity of the whole function is O(logN + N) = O(N)

at that point, why would we optimize the search if the function time is going to be linear anyways?

wouldn't linear search make it O(N + N) = O(N)? which is the same time complexity?

I realize that it will be faster to use binary search but I'm confused about the notational differences

[storm owl]

big O notation does not denote runtime, it is just a general overview of how complex a algorithm is, so you are right in that using binary search would not change the complexity, but realistically it is useful to apply when possible.

[jovial tartan]

ok, thank you

that clears it up

[half lotus]

It also goes the other way

Sometimes an algorithm with a better big-o complexity may be slower in practice

Perhaps it has poor performance for very small inputs, for example

[coral loom]

Just a quick question, can you access a class instance attribute/variable from an external Python script?

[lavish flame]

can someone please help me with this question

[trim fiber]

What are you mean? Do you have two scripts that are running simultaneously?

[lavish flame]

this is code I have written it doesnt work for the letters with same frequency

[trim fiber]

What exactly do you need? If you want complete solution it breaks rule 5

!rule 5

[halcyon plank]

Rules

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

[trim fiber]

Why do you have nested for loops?

for medicine in s:
  if medicine not in d:
    d[medicine] = 0
  d[medicine] += 1

You also should use better names for your variables because it's really hard to remember all of s, d, i, j and so on

[trim fiber]

You also can prepare d dict earlier using

for medicine in medicines:
  d[medicine] = 0

[lavish flame]

I wanna know how to distinguis between 2 letters with the same frequency

distinguish

[trim fiber]

You should update your first loop as far as I understand

medicines = list("ABCDE")
freqs = {medicine: 0 for medicine in medicines}
string = input()
for medicine in string:
  freqs[medicine] += 1

[lavish flame]

okay...yea but the final value of freqs is gonna be the same right

[trim fiber]

Then for input "ABAAACEBDAE" you got {'A': 5, 'B': 2, 'C': 1, 'D': 1, 'E': 2} so you can sort dict pairs by value by using sorted(freqs.items(), key=lambda item: item[1], reverse=True)

[lavish flame]

so this is going to give someting like A B E C D or A E B C D like on what basis will it sort if the frequencies are the same

[trim fiber]

If freqs are same then it will use original order as far as I know

Result is [('A', 5), ('B', 2), ('E', 2), ('C', 1), ('D', 1)]

[lavish flame]

okay thanks lemme try and get back to you in a min

thanks a lot! it worked!

[coral loom]

Yeah I do.. I'm making a Flask webapp that so far has the main application in app.py and another script which has a class with all its attributes and instance methods defined inside of it.. there isn't a way to access an instantiated object's class variable externally from app.py, is there?

[trim fiber]

Your welcome!

[trim fiber]

Can you spawn this script as a Python thread?

[coral loom]

@trim fiber Well, I don't really think I need to create any threads in my application as it doesn't require heavily extensive tasks that need to processed

[trim fiber]

Then if you want to communicate two processes you can use FIFO or something similar but if you want to easily manipulate object from other script the best solution is to use threads

[jovial hill]

Are you aware of any youtube tutorials that explain threads in detail?

[coral loom]

@trim fiber So the point I made earlier on is not possible other than making threads? There's no way to access a variable in class from another Python script?

[meager chasm]

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

ParseError: bad input on line 3

[pure parrot]

true should be True, no?

[meager chasm]

still no ):

ParseError: bad input on line 3

[agile sundial]

you shouldn't need to declare it global

just remove that part

[meager chasm]

NameError: name 'true' is not defined on line 3

[agile sundial]

true should be True, no?

[meager chasm]

i changed it

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

plzzz

[agile sundial]

is that the right link

[meager chasm]

ya

[agile sundial]

it seems to be the exact same as the one earlier

[meager chasm]

bcz i changed it beck to the global

[agile sundial]

sorry, i don't understand

[meager chasm]

me too

[agile sundial]

what did you change

[meager chasm]

.

as the link

what in the link in the code

[agile sundial]

did you change what i told you to change

[meager chasm]

ya

i deleted this

still no

so i bring the global brck

[heavy cloak]

Why is it returning a syntax error

https://cdn.discordapp.com/attachments/720723485596450878/809166241872740372/unknown.png

[halcyon plank]

`float.is_integer`

float.is_integer()```
Return `True` if the float instance is finite with integral value, and `False` otherwise:

```py
>>> (-2.0).is_integer()
True
>>> (3.2).is_integer()
False

[heavy cloak]

THANK YOU SO MUCH

UR INSANE @mystic basin

uh melio one more wuick question

alg = lambda x: True if (x ** 1/2).is_integer() == True else False

uh is that the proper way too use it?

its returning false

returns false when i sqeare root perfect squars

oh

why dont i have to specific if it is true or not

still dont work

16

and 25

they both got perfect squares

4 and 5

what

idk what thiws trickery is

but it just started working for me

idk my python IDE is sus

i mean

ill use visual studio from now on 😄

or something online

yeah

idk why its weird on mme sometimes

whaa

i used biger numbers

like

121

and

it retunred false on 121

for some odd reason

ok dude now its returning true

dont mind this

its pycharm 🙂

lmao

[fiery cosmos]

bruh

[heavy cloak]

I see

thanks Melio-

[shy gate]

Is there a way to generalize a root finding algorithm to solve generalized equations?

Basically i have some expensive function to calculate in a hot path of code: ```python
def f(x: int) -> float:

stuff happens here

I want to find a value for

f(x) < N
f(x+1) > N```

Basically the largest integer to meet the criterion.

right now I'm using a basic bisection method, but I was curious if i could steal from root finding and use a secant/interpolation/combination method? Or if this particular problem has a specific name for me to look up the literature on

[chrome ermine]

This might be a dumb question. I have a list of hardware crash data for anytime a piece of HW crashes.

Example:
[dsp crash] Pmd.34938249324 e ent=12 pmasdaaa cf4
[dsp crash] Pmd.34933449324 ee nt=12 pmasdaaa cx

Using difflib, i can match them but running into a problem where i'm trying to build a dict that has say the first crash text and the count anytime it sees a match thats ~90% the same.

thoughts?

[warm solstice]

How do I go about solving this kind problem f program? The problematic part is figuring out the amount of days it takes to update "the servers" pretty confusing

[trim fiber]

I don't like videos as a form of learning but everything depends on you - if you like then use it 🙂
However remember that at some experience level there are no more video tutorials anymore 😦

[trim fiber]

Maybe there is but I don't know it. If you have two Python threads inside Python process you have Python which can communicate data from one thread to another. From another hand if you have two processes in your OS (can by Python programs or whatever) you can communicate data from one to another by using OS built-in methods (like FIFOs). There is a problem because you should write some kind of encoder/decoder that encodes your Python data into binary to transfer it through OS methods and you need to have decoder on the other side to decode binary into Python objects for example.
The easiest case is to spawn new Python thread inside script and use Python objects to communicate those threads.

[jovial hill]

I don’t mind reading aswell, but I can pick up concepts with videos quicker especially watching them x2

[rose kraken]

anyone coder here dm me

[coral loom]

I'm not sure if I should do that in my application just yet as I've got few functionalities that I've need to implement

We can use deepcopy to copy variable's content, if it's to copy the nested items inside an object, right? i.e. a dictionary with a list of string names and integer values

I'm trying to define/rename an instance attribute in a Child class and copy over the content from a dict object declared in a Parent class --- but no values actually gets stored/shown (even when I instantiate a Child class instance member)

from copy import deepcopy
class Child(Parent):
    def __init__(self):
        super().__init__()
            self.dict = deepcopy(self.parentDict)

@wild urchin I think I've got a problem when I deepcopy data found in the original dict object onto a new variable object - no values gets stored on it

[wild urchin]

Can you post a minimal code snippet that shows this issue you're having?

The code above doesn't include what the Parent class looks like

I'd suggest doing so in a help channel, rather than in this topical discussion channel.

[coral loom]

I'm on #help-chili

[crimson jacinth]

@vocal gorge after thinking about it more I realized I’m not really interested in the entire table but just the frequency of values

From that problem in help-chlorine

so for example, “how many values are 2000 in the table” etc

so I’m thinking to create a dictionary with the keys as values and increment each access

[vocal gorge]

the problem is that you're building the table by incrementing elements multiple times

so you can't easily transfer that into another form, I don't think

[crimson jacinth]

I see

[frank harbor]

how do you do the python typing for discord, is it ``?

[glossy breach]

Three "`"

[zenith pagoda]

Hi, can someone help me to visualize or understand the sentence below.

[lean glade]

I guess the array would contain int32s, and each int, when converted to binary, would contain 32 ones and zeros, which would represent true or false, respectively

And the array would have a size of 128 million

[zenith pagoda]

@lean glade is bit vector is an array of arrays of int32s?

[vocal gorge]

Uhh, no? Just an array of int32s.

well, they might want a vector of int32s. A vector being a dynamic array.

[prisma sedge]

i just started to write a code for a simple binary tree and i have an attribute error. can someone help? i'm new

class Node(object):
def init(self,value):
self.value = value
self.left = None
self.right = None

class BinaryTree(object):
def init(self,root):
self.root = Node(root)

def print_tree(self, traversal_type):
    if traversal_type == "preorder":
        return self.preorder_print(tree.root, "")
     else:
        print("Traversal type " + str(traversal_type) + " is not supported.")
        return False

def preorder_print(self, start, traversal):
   
    if start:
        traversal += (str(start.value) + "-")
        traversal = self.preorder_print(start.left, traversal)
        traversal = self.preorder_print(start.right, traversal)
    return traversal

[zenith pagoda]

thanks

[crimson jacinth]

So this isn't a python question per se, but I have an array with 4 billion elements, and I have to iterate over all that, and increment each [x,y] for a given function. Some [x,y] will never be accessed, but others may be accessed multiple times.

what are some ways i can speed up this traversal? RAM isn't an issue

i will likely implement this in C as well.

[vocal gorge]

Isn't it the same task you did earlier, which could be vectorized with .add.at?

oh, in C, I see. Yeah, then I don't have any advice besides "write the loop in a sideeffects-free way and hope for the compiler to optimize it right, preferably with vectorization".

in C, I see
...pun not intended.

[crimson jacinth]

@vocal gorge well I actually ended up doing it in C and surprisingly it finished in 2 minutes but in Python the loop ran for several hours

[vocal gorge]

that's very possible if the Python one was just a loop too

[crimson jacinth]

What do you mean?

The function is pretty simple, just takes a lot of memory, it should take the same time in Python I’d imagine

But it did not

[trim fiber]

Python is slower than C even when you do a simple loop

[crimson jacinth]

but like, orders of magnitude slower?

[trim fiber]

I created simple functions in C and Python to calculate entropy and as far as I remember C code executes about more than 3 times faster

[crimson jacinth]

i see

possibly something to do with the data types

[trim fiber]

I think that creating Python objects is overwhelming

In C you can use simple types like int or char[], Python needs to create huge structures under the hood

[agile sundial]

that's part of it, yeah

[vernal stirrup]

i have an np array t = [3,2,4,2,4,NaN,NaN] and i have an array tisNaN = [False,False,False,False,False,True,True] (from np.isnan(t) and i want to delete the nan values out of t

how do i do it?

[fiery cosmos]

hi guys, Im not sure if this is the right channel but I want ´how can I create a list out of copy pasted text? I basically want a programm in which one copy pastes their insta followers and their insta following and I then want the programm to check who follows you but not them, who you follow but they dont back..... If i copy paste my followers, after every follower it says "profile picture", so I would like the list replace "profile picture" with a comma. Im very new so maybe there is an easy function to do this, but I have been googling for a while and didnt quite get what Im looking for....

[shy gate]

I'd actually look into using the instagram API or a third party instagram api

would be much easier to just authenticate a user and log in and pull that information instead of having to copy and paste it yourself

[fiery cosmos]

but for me as a programmer API are far out of reach tbh

can I like replace "profile picture" with "," and then its a list?

i was trying this, I put it together from a few forums

s = input("Copy paste your followers here")
s = re.sub("profile picture" , "," , s)
f.seek(0)
f.write(text)
f.truncate(0)
print(s)

[dense rain]

what does python do?

[fiery cosmos]

but it tells me "re" is not defined

[pure terrace]

Hello how can I delete one event object from the following dict:
my_dict = { user_id: { event_id: {'name': event, 'time': time} } }

del my_dict[user_id][event_id]

[trim fiber]

Right, here you are

[lavish violet]

Can i speak?

[sudden kernel]

how would I do this:

genuinely lost

Note that another sample input can be 14 X X X X 18 X 16 X and output can be ```
14 16 18
14 16 18
14 16 18

[violet bramble]

Hey anyone know how to solve sudoku in python using the ac3 constrain satisfaction algorithm

[pale prism]

do this on paper first. if you have two numbers from one line, how do you calculate the third? check with some simple values and then with letters: if you name the elements in the line a b c, how do you find value of b when you have a and c?
work from there - do the maths, try coding what you found out. that will cover some points
analyse what to do if you have more x's - e.g in your example with 6 x's, are there more solutions? 😉 how do you know when there are more solutions? (answer: ||that's the only solution there - we have a system of 6 independent linear equations, and we have 6 variables; more solutions are possible for "at least 7 x's" case which is for more points||)

[clever stratus]

Let's say I have a set, setA={dog, cat, mouse}, I would like to create a data structure with the strings in Set A, so it would make:

dog = {}
cat = {}
mouse = {}

is that possible?

*name the data structures with the strings in SetA

[pale prism]

the easiest thing would be to just do a dictionary with those as keys. then you'd be able to do my_dict["dog"] to access the dog's structure
because if you name them from a set, how are you gonna use them in your code? with dict, you can access those structures by their string name

[main flower]

why would u do that tho

[clever stratus]

actually I can just create a class lol..

just realized that

I have a list of email addresses with data associated with them, so I wanted to create a set named after each unique email address

[unreal rain]

I'm wondering how search data structures like a trie works in the real world. Is the whole trie stored in memory or is this search / storage capability on the database level?

[grim dove]

Hi, someone could help me create this function that would allow me to do that ? Thx x)

code = r"""
int a = 5;
foo2(16, 255);
...
"""

code = function(code) 

print(code)

Output:
int a = 0x5;
foo2(0xA, 0xFF);
...

[vernal stirrup]

print(code)```

or do you want the function to format the string?

[grim dove]

yes the function 😂

[vernal stirrup]

use string.split(";") and work it togeteher with "\n" in between?

can you explain the purpose of the method?

why you want a function like that

[grim dove]

no 😂
I want a function to convert decimal to hexadecimal in a string

[vernal stirrup]

oh i havent seen the difference

i am lost sorry

that explains a lot i am really sorry

[grim dove]

ah too bad, I hope someone else will have the solution 😅

[robust trellis]

def check_int_and_convert(s): if s[0] in ('-', '+'): if s[1:].isdigit(): return s[0]+hex(int(s[1:])) elif s.isdigit(): return hex(int(s)) else: return s

[trim fiber]

You can use exec but I recommend to use strings from set as keys in some dict

names = {"bat", "cat", "dog"}
struct = {name: {} for name in names}

[pure terrace]

Hello I'm trying to convert an object that contains a nested dict into a dictionary itself:

def to_dict(self) -> dict:
        data = {
            "notifications": self.notifications
        }
        return data

new_not = Notification()
new_not.notifications['users'][_id] = {}
new_not.to_dict()

I feel like I might be doing sth wrong

[trim fiber]

What is the problem?
You should consider using copy.deepcopy

[pure terrace]

I fixed

[keen hearth]

Hey 😄 It probably depends on the application, to be honest.

[noble vector]

Hey guys, reading Algorithms in a nutshell, do I just sit with the complexity or should I focus on a prerequisite that I didn't know I needed?

I get the data structures part but the notations of the algorithms is just convoluted for me

[eager hamlet]

if you just mean complexity notation, it isn't that hard to understand

http://www.usaco.org/index.php?page=viewproblem2&cpid=765
so uh i'm working on this problem, and i know that it involves bfs
but how do i do this in linear or linearithmic time
because for each state i also have to keep track of the pies given

maybe #databases would be better

[icy crane]

@eager hamlet thanks.…..

[noble vector]

I mean sure, I guess to read more will do

[noble vector]

The definitions were in the next chapter lol

[fair prairie]

how to read these stuff

[vocal gorge]

This is the definition of the O-notation.

Basically, if there exists some constant C such that, for all sufficiently large n, T(n) <= C F(n), then T(n) is O(F(n)).

For example, T(n) would be O(n^2) if T(n) <= C n^2 for some C and for all sufficiently large n.

[fair prairie]

@vocal gorge 🤔 its soo confusing

[vocal gorge]

some examples:

1. 1 - exp(-n) is O(1)
2. 5 n^3 - 10 n^2 + 5n - 120 is O(n^3)
3. 3log(10n) + 10n is O(n)
4. 100000 n^1000 exp(-n) is O(1)

[fiery cosmos]

how can I spread (disperse) a set of numbers from n1 to n2 with an exact distance of each other ? Example, dx = 5 n1 = 1 and n2 = 3, so answer is 1, 1.5 , 2, 2.5 , 3

i am trying to figure out what formula to use in order to find that answer.

[vocal gorge]

Well, one simple way to find it is to note that the formula must be linear, so it has the form f(n) = a * n + b. The coefficients a and b can be found by requiring f(0) = n1, f(dx-1) = n2

(of course, you can also just realise the distance must be (n2-n1)/(dx-1), because there are dx-1 increases between the first and the last point).

[fiery cosmos]

I understand this part, but still not too sure on how to find the 0,5 gap that seperates 1 to 3 in a dx=5 manner

not sure if my english is very good at explaining what i mean

apologies

[vocal gorge]

...because (3-1)/(5-1) = 0.5?

[fiery cosmos]

oh oh okay damn. that was easy

is that formula linked with something a bit more general ?

[vocal gorge]

alternatively, we have a general linear function a n + b. Requirements:
1)f(0) = 1, meaning b = 1.
2)f(4) = 3, meaning 4 a + b = 3, therefore a = 0.5

[fiery cosmos]

oh okay i get it now

many thanks @vocal gorge !

[vocal gorge]

And in general, the formula is f(n) = n_1 + (n2-n1)/(dx-1) * n - the formula for a line drawn through points (0,n1) and (dx-1,n2)

[fiery cosmos]

why is he not using 1 , to solve ?

also this exercise has to do with Riemann sum

[vocal gorge]

I can't read Greek(?), so I don't know what you mean.

[eager hamlet]

http://www.usaco.org/index.php?page=viewproblem2&cpid=765
so uh i'm working on this problem, and i know that it involves bfs
but how do i do this in linear or linearithmic time
because for each state i also have to keep track of the pies given so i don't accidnetally give 2 of the same pies for the same state

[queen ruin]

what's the dunder that executes on object creation

before init

[trim fiber]

Are you asking about __new__?

[queen ruin]

ahh yes thank you, google sucks at showing these results

[edgy haven]

Are there any good books to learn algorithms that have examples in python

[dry crow]

Grokking Algorithms

[gilded turtle]

guys i need help in minimax algorithm

I am trying to make a tic tac toe Ai using minimax

[halcyon plank]

Hey @gilded turtle!

Uh-oh! It looks like your message got zapped by our spam filter. We currently don't allow .txt attachments, so here are some tips to help you travel safely:

• If you attempted to send a message longer than 2000 characters, try shortening your message to fit within the character limit or use a pasting service (see below)

• If you tried to show someone your code, you can use codeblocks
(run !code-blocks in #bot-commands for more information) or use a pasting service like:

https://paste.pythondiscord.com

[gilded turtle]

https://paste.pythondiscord.com/raw/uxobevinop

it keeps throwing an error

Traceback (most recent call last):
File "D:\Coding\Projects\Unbeaten_X&O\main.py", line 172, in <module>
minimax(Board, 6, True)
File "D:\Coding\Projects\Unbeaten_X&O\main.py", line 156, in minimax
e_val = minimax(bo, depth-1, False)
File "D:\Coding\Projects\Unbeaten_X&O\main.py", line 164, in minimax
e_val = minimax(bo, depth-1, True)
File "D:\Coding\Projects\Unbeaten_X&O\main.py", line 156, in minimax
e_val = minimax(bo, depth-1, False)
File "D:\Coding\Projects\Unbeaten_X&O\main.py", line 162, in minimax
index = Board.index('-')
ValueError: '-' is not in list

[coral loom]

Just a fairly quick question, what are the different ways to do "getters" and "setters" in Python, let's say for a variable named myList of the datatype, list, initialised normally in a class constructor?

[flat sorrel]

class MyClass:
    def __init__(self, lst):
        self.my_list = lst

    @property
    def my_list(self):  # getter
        return self._my_list

    @my_list.setter
    def my_list(self, value):  # setter
        self._my_list = value

[stable pecan]

class MyProperty:
    def __set__(self, instance, value):
          instance.__dict__[self.name] = value

    def __get__(self, instance, owner):
          if instance is None:
              return self
          
          return instance.__dict__[self.name]

    def __set_name__(self, owner, name):
          self.name = name

class MyClass:
    my_list = MyProperty()
    def __init__(self, lst):
        my_list = lst

[heady plaza]

Huuu anyone to explain me this error plz...
Traceback (most recent call last): File "compiler.py", line 7, in sol = solve(expr) File "/usr/local/lib/py/dist-packages/sympy/solvers/solvers.py", line 1162, in solve solution = _solve(f[0], *symbols, **flags) File "/usr/local/lib/py/dist-packages/sympy/solvers/solvers.py", line 1444, in _solve soln = _solve(m, symbol, **flags) File "/usr/local/lib/py/dist-packages/sympy/solvers/solvers.py", line 1498, in _solve f_num, sol = solve_linear(f, symbols=symbols) File "/usr/local/lib/py/dist-packages/sympy/solvers/solvers.py", line 2072, in solve_linear eq = lhs - rhs TypeError: unsupported operand type(s) for -: 'Tuple' and 'int'

Ooo

I just understood

[coral loom]

Could you talk through explaining how this works internally, if you don't mind @stable pecan ? @flat sorrel approach is fairly the simple way... easily understood 👍 😀

[fiery cosmos]

You tried to subtract an integer from a tuple 🙂

[fiery cosmos]

Sometime happens if you put somewhere a comma... 🙂

where you didn't want to...

[heady plaza]

Thhhhx

U awesome !!

[stable pecan]

i would read the descriptor how-to in the python docs: https://docs.python.org/3/howto/descriptor.html

this is the order of attribute lookup python uses

[drowsy bolt]

hey how do i use excel cell value as input for driver.get(cellValue) to vist that url in cell. I have already imported the cell value and workbookwith openpyxl

[tame minnow]

Hi! I am making a project regarding graph theory in python.
Is there a algorithm to split a minimum spanning tree into many paths? (Path is basically a line with 2 ends only) attached are 2 images which might be helpful.
I couldn’t find any answers on google.

[grizzled dragon]

This is an interesting problem!

Are you trying to turn the connectogram @ the top, into something like what you display at the bottom? Do you know what sort of constraints, or additional rules ?

[tame minnow]

Yeah

The only rule is that the line can only have 2 ends, no branches

[grizzled dragon]

Exhaustive search of all possibilities?

non overlapping? overlapping?

[tame minnow]

Overlap is fine

I think the search could be limited at some point, and the time complexity will be very high as the nodes increase

[grizzled dragon]

yes, of course, as well as the degree of each node

how are you representing the top image?

[tame minnow]

I have a nxn distance/adjacency matrix

[grizzled dragon]

NxN with 1's and 0's denoting connection?

[tame minnow]

Nxn for weight, in this case it’s the pixel distance

[grizzled dragon]

what is the weight needed?

[tame minnow]

Btw it is a complete graph, all the nodes have a weight to every other node

[grizzled dragon]

yeah, but I don't think you need to weight each node to answer the question you posted at the very top

[tame minnow]

Oh yeah

[grizzled dragon]

It's easier to visualize a way forward if you cast the graph in a different representation, e.g. not the adjacency matrix which I think you're using

because, to code this, you have to know where to go once you're at a given node.

you also have to store the paths somewhere

Try the adjacency list.

[tame minnow]

I was thinking of a array eg 1,3,5 connects 1 to 3 to 5

Is there other ways to represent a tree?

[grizzled dragon]

I've done a similar problem to this one, but using adjacency lists. The code was messy AF, but it worked always

https://en.wikipedia.org/wiki/Adjacency_list

[tame minnow]

Oh so something like a dictionary?

[grizzled dragon]

yeah, like a dictionary. I am not sure if this is efficient but it will at least help you visualize a programming solution

it is harder to do visualize what is going on with the adjacency matrix representation

"An implementation suggested by Guido van Rossum uses a hash table to associate each vertex in a graph with an array of adjacent vertices. In this representation, a vertex may be represented by any hashable object. There is no explicit representation of edges as objects"

Guido van Rossum, Mr Python Inventor himself

So, to find your paths, you have to figure out some way of coding through all the permutations that the dictionary / hash table produces. There are additional problems that arise when you try to avoid repeating paths, not going around in circles, etc.

[tame minnow]

Do I basically connect each end to another end?

[grizzled dragon]

the structure of the graph will obviously be encoded in the adjacency list. What your code needs to do is simply inspect this structure aided by the how it is encoded.

like the A-B-C triangle in the preview

a={b,c}

b={c,a}

c={a,b}

[upper tartan]

(Sorry if there’s a better channel for this.)

Are there any PEP guidelines (or other principles) on whether you should make your class subscriptable or not?

[grizzled dragon]

if you start in a, you notice that there are 2 directions: b & c. Then your code will have to explore each separately, with the first path a-b, and the next a-c.

etc.

[tame minnow]

Ah I see, I’ll try to implement this

Do you think it will be good to start at a node more at the center?

[grizzled dragon]

I don't think it matters.

this should work regardless of the starting point

[tame minnow]

Cool

Thanks for the help 🙏

[grizzled dragon]

btw, as I said, I did this in the past, but with a constraint of 2 edges.

and it was a nightmare scenario of nested loops and gotos

(C++, not python)

[tame minnow]

Do you think I can have a look?

[grizzled dragon]

tbh, it would take you less time to sort it out on your own than it would to figure out my spaghetti

[tame minnow]

lol

Ok I’ll try first

[grizzled dragon]

“Do or do not. There is no try.”

[tame minnow]

😂

[half gazelle]

words = ['book', 'pencil', 'pen', 'note book', 'sharpener', 'rubber'] 
def arraySearch(array, search):
    return True
print(arraySearch(words, 'note book') if 'Vrai' else 'Faux')
print(arraySearch(words, 'dog') if 'Vrai' else 'Faux')```

help me understand?

algo termaire ?

[tame minnow]

arraysearch doesn’t seem complete

[half gazelle]

okay !!thanks

words = ['book', 'pencil', 'pen', 'notebook', 'sharpener', 'rubber']

def arraySearch(array, search):
    for i in range(len(words)):
        if words[i] == (array, search):
            print(arraySearch(words, 'note book') if 'VRAI' else 'FAUX')
        elif words[i] != (array, search):
            print(arraySearch(words, 'dogs') if 'VRAI' else 'FAUX')

    return True```

like this

[tame minnow]

What’s your question?

Also you could just use if item in array: ...

[half gazelle]

my teacher gave me the first code but didn't give us any instructions, I'm looking for a way to understand, I just know that it has something to do with a sorting algo!?

thank you for these precisions

[tame minnow]

What’s vrai and faux?

[jovial hill]

Hi, I have two variables but I want them to have difference reference ids:
self.x = aep[1] self.y = aep[1] self.x[key] = 'test' self.y[key] = 'test2' print(self.x) #prints key with value test2 print(self.y)#prints key with value test2

How can avoid this and have both variables to have different references so self.y prints test2 and self.x prints test

[vocal gorge]

You need to make a copy of aep[1], rather than have two references to the same object. Use self.y = aep[1].copy() (or the deepcopy library if this is a nested object you need to fully copy).

(also, it's more of a question for a help channel or #python-discussion)

[jovial hill]

oh sorry

https://stackoverflow.com/questions/2465921/how-to-copy-a-dictionary-and-only-edit-the-copy

but thanks anyways

[vocal gorge]

Yup, that's pretty much it. In Python, all assignments are by reference - a copy is never made without explicitly doing so.
(really, most other languages are the same - only primitive types are passed by value, a big object like Map would never get implicitly copied. In Python, there also aren't such primitive types).

[jovial hill]

Thanks a lot!👍

[solar musk]

hello, so i want to create a basic search mechanism in my website but i have trouble making out the logic for it. so the idea is that a user searches something using the search bar right? so i want to show records from database related to quries that user has searched number of times. but i still want to take into the account the time factor. for example: if user searched for oranges 7 times but that was a month back. and the user searches for apples 6 times but it was just a week back. the latest search should have more priority right? what kind of algorithm i should use here? im sure there's already an algorithm for this which exists. any intresting read that you can point me to would be great?

[dusk quest]

hey i created this

[halcyon plank]

Hey @dusk quest!

Uh-oh! It looks like your message got zapped by our spam filter. We currently don't allow .txt attachments, so here are some tips to help you travel safely:

• If you attempted to send a message longer than 2000 characters, try shortening your message to fit within the character limit or use a pasting service (see below)

• If you tried to show someone your code, you can use codeblocks
(run !code-blocks in #bot-commands for more information) or use a pasting service like:

https://paste.pythondiscord.com

[dusk quest]

omg why

can anyone dm me if u are good at python and help me out with a code

[vocal gorge]

why don't you post it in a help channel instead? #❓｜how-to-get-help

[dusk quest]

noo it still shows

spam and stuff

[vocal gorge]

or use a pasting service (see below)
@dusk quest

[halcyon plank]

Hey @dusk quest!

It looks like you tried to attach file type(s) that we do not allow (). We currently allow the following file types: .3gp, .3g2, .avi, .bmp, .gif, .h264, .jpg, .jpeg, .mov, .mp4, .mpeg, .mpg, .png, .tiff, .wmv, .psd, .ai, .aep, .xcf, .mp3, .wav, .ogg, .webm, .webp, .flac, .afdesign, .m4a, .csv.

Feel free to ask in #community-meta if you think this is a mistake.

[dusk quest]

;-;

[vocal gorge]

...why don't you read the bot's message?

Or this one, at least:

!paste

[halcyon plank]

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.

[lost osprey]

milfs

[full stream]

Would webscraping somewhat fit here?

[fiery cosmos]

hi, I was reading an algo & ds book and I just had a question.

so, arrays store elements contiguous in memory. arrays (unlike linked lists) can have random access, so you can read the 5th index (which is O(1) compared to reading the 5th index of a linked list where you traverse the elements before it, making it O(n)). So, linked lists have sequential access.

So my question is, when using python (for example) using lists, is that saved in RAM as it's random access?

[vocal gorge]

Python lists are, under the hood, vectors of pointers to PyObjects (which is the class of all Python objects, ultimately).

A vector is a dynamic array - it's an array that gets resized when it starts running out of space. So yeah, it's O(1) random access. Not sure what you mean by saved memory - access complexity and memory usage aren't related in an obvious way (though linked lists are terrible in both, and in general - it's a data structure that everyone gets taught, but is rather rarely used).

[fiery cosmos]

i see, thank you very much for the explanation! I think I just confused lists being "random access" and made a link with RAM "random access memory" and thought there was a link. i must say, this algo stuff is pretty interesting so far 🙂

also it probably doesn't help that python is a high level language so we cant handle our own memory and understand it, there might be a bit of obfuscation there

[vocal gorge]

Yup, that's pretty true. It's a bit harder to learn DSes in Python than in compiled languages, because implementing them manually in Python is not very useful (any implementation you can make in pure Python will often be literally orders of magnitudes slower than the C-based implementations of the standard library). You still need to know DSA to know when to use the right data structures, though, so it's by no means useless even for Python.

and yeah, being far removed from handling memory makes it harder to understand too

[quasi basalt]

can someone help with sklearn here

[main flower]

Well, It's probably connected to machine Learning or data science so you should probably ask in #data-science-and-ml

But I don't know your question so idk

[vernal stirrup]

i want to create a boxplot via pandasDataFrame.boxplot(column="dataColumnName", by="seperatingColumnName") but the data in the "dataColumnName" is a list and only the last value of the list should be used. Is there an efficient and clean solution for my problem?

[rancid patio]

How can i get the last date by symbol in this dict of tuples

 ('2020-12-02', 'FB'): -5025,
 ('2020-12-04', 'FB'): 1950,
 ('2020-12-01', 'AAPL'): 15000}````

[sullen summit]

from dateutil.parser import parse
my_dict = {('2020-12-01', 'FB'): 2000,
 ('2020-12-02', 'FB'): -5025,
 ('2020-12-04', 'FB'): 1950,
 ('2020-12-01', 'AAPL'): 15000,
 ('2021-12-01','test'): 0000}


most_recent_date = '1900-01-01'
symbol = None
for key, value in my_dict.items():
    if parse(key[0]) > parse(most_recent_date):
        most_recent_date = key[0]
        symbol = key[1]

print(symbol)

is this the sort of thing you're going for?

[rancid patio]

[{'FB':'2020-12-04'}, {'AAPL':'2020-12-01'}]

im looking for something to the sorts of

    from x
    group by sym```

[sullen summit]

oh you want them sorted?

[rancid patio]

i just need the last date for each sym

[sullen summit]

sorry, I'm not sure I understand. You're saying you want to pass the function a symbol, and then have it return the last date in the dictionary associated with that symbol?

so here, you would pass it 'FB' and it would return '2020-12-04'?

[rancid patio]

I wouldnt be passing in a symbol. I just need to for each symbol, in this case there is only two FB and AAPL, return me the latest available date

[sullen summit]

should it return that in another dictionary?

[rancid patio]

yeah thats perfectly fine

[sullen summit]

try this and see if it does what you want:

from dateutil.parser import parse
my_dict = {('2020-12-01', 'FB'): 2000,
 ('2020-12-02', 'FB'): -5025,
 ('2020-12-04', 'FB'): 1950,
 ('2020-12-01', 'AAPL'): 15000,
 ('2021-12-01','test'): 0000}


symbol_dict = {}

def create_symbol_dict():
    for key, value in my_dict.items():
        if key[1] not in symbol_dict.keys():
            symbol_dict[key[1]] = key[0]
        

def update_symbol_dict_dates():
    for key, value in my_dict.items():
        if parse(key[0]) > parse(symbol_dict[key[1]]):
            symbol_dict[key[1]] = key[0]

create_symbol_dict()
update_symbol_dict_dates()
print(symbol_dict)

[rancid patio]

yeah this is great!

[sullen summit]

you know how it works? if you have any questions on what I did, let me know

[rancid patio]

great,yeah i understand. The only thing i was thinking was a will probably want to use a set for the tickers

instead of a function

[sullen summit]

yeah, it might be cleaner that way

[ember locust]

hey guys, anyone know Java and can help me go thru each problem on the codility quiz website so I can be prepared for a job interview soon?

[flat sorrel]

Sorry, this is a Python server so we won't offer help on Java outside of the off-topic channels (and even so, you might want to visit the Java server instead)

[ember locust]

could you link me to java server plz?

i'm totally new here

[flat sorrel]

https://discord.gg/GzvQjhv

[ember locust]

thx buddy

[flat sorrel]

np

[trim fiber]

Isn't is this? https://docs.python.org/3/library/logging.html#logging-levels

@fiery cosmos How about call help(fxcmpy.fxcmpy)?

Your welcome

This library uses logging under the hood, here is the source code: https://github.com/chaipat-ncm/fxcmpy/blob/master/fxcmpy/fxcmpy.py#L121-L126

https://github.com/chaipat-ncm/fxcmpy/blob/master/fxcmpy/fxcmpy.py#L146-L152

I don't know why there are 10, 20, 30 and so on but when you set for example log level to warn (30) you get logs from error too because 40 > 30 (so you get all log levels above choosen)

Your welcome!

https://giphy.com/gifs/memecandy-jUEuQU7RGyYsdnXHvF

[half gazelle]

names = ['Tamata', 'Nicolas', 'Marie-Claude', 'Oriane', 'Florian', 'Yvanne', 'Jordan', 'Joyce', 'Julien', 'Clément', 'Jeremy', 'Daren', 'Mikaele']
def arraySort(myArray):
  # code here ...
print(arraySort(names))```

I have to sort all the names in alphabetical order, I have to use the sort by insertion, which could make me rotate the code in all directions but no result.

without using .sorted

[trim fiber]

What is the problem? Where is your algorithm?

[half gazelle]

names = ['Tamata', 'Nicolas', 'Marie-Claude', 'Oriane', 'Florian', 'Yvanne', 'Jordan', 'Joyce', 'Julien', 'Clément', 'Jeremy', 'Daren', 'Mikaele']
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']

def arraySort(myArray):
    for i in myArray:
        if i in alphabet:
            return myArray

        
print(arraySort(names))

[trim fiber]

First of all you can use list(string.ascii_letters) to create array of letters

Secondly - I cannot write the algorithm instead of you because it breaks rules

!rule 5

[halcyon plank]

Rules

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

[trim fiber]

Show your minimal effort please

[half gazelle]

I understand but I'm just looking for a way out.

[trim fiber]

Take a look at pseudocode here: https://en.wikipedia.org/wiki/Insertion_sort

[half gazelle]

thx

[trim fiber]

You can come here when you will have a problem with some part for implementation

[half gazelle]

okay thx

[mint jewel]

(get_data,) is a tuple, but (get_data) is just get_data

(value) can't be a tuple, since it would break parentheses for math

add_callbacks expects some iterable of callbacks

but (5 + 6) * 8 is 88, not a tuple.

in order to create a tuple with a single element in it, you need a comma

(5 + 6,) * 8 is (11, 11, 11, 11, 11, 11, 11, 11)

it is not great, but there is real way around it

you could also just do [get_data] and avoid this whole issue

[coral loom]

I don't suppose anybody can help me out with something? So I'm creating a pandas **dataframe **from a dictionary, which is populated with mixed **entities **as keys (that includes names of country/people/object etc) and the **occurrences **of that particular entity is stored as the corresponding **value **... Here's how I'm making a dataframe from the dictionary key-value pair items... ```py
def convert_dict_into_dataframe(self):
df = pd.DataFrame.from_dict(self.myDict, columns = ['Entities', 'Frequency'])
return (df.head())

Are there any ways to simply check which elements in a df column i.e. Entities, is contained (recognised as a country) in a list of predefined country list object let's say called countryList...? And then with this, be able to extract those identified elements, "countries", and add it to a new column in the **dataframe **table where it just contains data fields of countries.. is this something which can be done?

[zenith pagoda]

May I ask what is the time complexity when an integer x keeps on divided by 10? Is it O(log(x))?

Let say x = 123 and

while x > 0:
  # Some if-block going on here
  x = x // 10

[trim fiber]

I think it's rather O(n)

However... It depends on number of digits... So number of digits can be calculated by log_10(x) so...

[zenith pagoda]

Additionally, so that's a question with a solution. And the solution says

There are roughly log⁡_10(x) digits in x.

What do they mean by that?

[trim fiber]

Ya... So you are right

It's O(log(x))

Sorry for mistake

[zenith pagoda]

What do you mean by it can be calculated by log_10(x) ?

[trim fiber]

When you want to know number of digits of some number x in base of y you count how many multiplications of y are in x

So you want to find such n that y^n = x

Am I correct?

So if you want to find n then n = log_y(x)

[zenith pagoda]

Oh yeah, math. I forgot that.

[trim fiber]

Ya, math. Queen of the science

[zenith pagoda]

Thanks for reminding me.

[trim fiber]

Your welcome!

[runic moss]

🔥

[wise bronze]

Hi, how can i make a thread to when i input a word this for loop restarts

while True:
    downloadFiles()
    for remaining in range(10, 0, -1):
        sys.stdout.write("\r")
        sys.stdout.write("{:2d} seconds remaining.".format(remaining)) 
        sys.stdout.flush()
        time.sleep(1)

    sys.stdout.write("\rComplete!            \n")

This for is a timer countdown

[scarlet gate]

I have a doubt in your code can I ask?

[heavy cloak]

translate = lambda x:(ord(i).split() for i in x)
<generator object <lambda>.<locals>.<genexpr> at 0x00000249AF5EC890>

thats hte output

why is it not returning the unicode of the letters in the string in a list

[wise bronze]

yes

[scarlet gate]

you are clearing the output right

but you are clearing the output before sleep

which clears the output and waits for a sec and then show the output and clears it immediately and so on

[kindred coyote]

So here i have two programs that output the same thing. ```py
m = int(input())
n = int(input())
brushes = input()
stroke = []

colors = [['B' for _ in range(n)] for _ in range(m)]
for i in range(int(brushes)):
g = input().split(' ')
if stroke.count(g) == 1:
stroke.remove(g)
else:
stroke.append(g)
def changeColumn(num,colors,index):
if num == 0:
return colors
colors[num-1][index] = 'G' if colors[num-1][index] == 'B' else 'B'
num -= 1
changeColumn(num,colors,index)

def countGold(c,options,i):
if options == []:
s = 0
for l in c:
s += l.count("G")
print(s)
return
area = options[i][0]
times = int(options[i][1]) - 1
if area == "R":
c[times] = list(''.join(c[times]).replace("G","A").replace("B","G").replace("A","B"))
elif area == "C":
changeColumn(m,c,times)

options.remove(options[i])
countGold(c,options,i)

countGold(colors,stroke,0)

and and ```py
c = int(input())
rows = int(input())
brush = int(input())
strokes = []
tc = []
for i in range(c):
tc.append('B' * rows)
for i in range(brush):
strokes.append(input().split(' '))

for i in range(brush):
if strokes[i][0] == 'R':
new_str = ''
for char in tc[int(strokes[i][1]) - 1]:
if char == 'B':
new_char = 'G'
elif char == 'G':
new_char = 'B'
new_str += new_char
tc[int(strokes[i][1]) -1] = new_str
elif strokes[i][0] == 'C':
new_str = ''
for j in range(c):
if tc[j][0] == 'B':
old_char = list(tc[j])
pos = strokes[i][1]
old_char[int(pos)-1] = 'G'
tc[j] = (''.join(old_char))
elif tc[j][0] == 'G':
old_char = list(tc[j])
pos = strokes[i][1]
old_char[int(pos)-1] = 'B'
tc[j] = ''.join(old_char)

s = ''
for t in tc:
s += t

print(s.count('G'))

i was wondering which one is more efficient

[fiery cosmos]

Hello guys !
Does someone can help me on an implementation of the IDA* algorithm with Manhattan heuristic ?
Question here : https://stackoverflow.com/questions/66264958/how-can-i-implement-ida-algorithm-in-pyhton-for-15-puzzle-problem

[lean ice]

im trying to write a function that takes in a 2D list and if there's any duplicate values, merges the sublists:
[[1,2,3],[1,4,5],[6,7,8],[1,9,10],[12,3,4]] -> [[1,2,3,4,5,9,10,12], [6,7,8]]

def merge(lst: list) -> list:
    next_value = 1
    all_items = []
    for sub in lst: # group all items to check for dupes
        all_items += sub
    merged = False
    while len(set(all_items)) != len(all_items): # check if dupes
        for sub in lst: 
            for item in sub:
                for _sub in lst: # iterate through each sublists items and check if they are in any other sublist
                    if item in _sub and (sub != _sub or id(sub) != id(_sub)): # ids have to be checked in case 2 sublists have the same values
                        print(f"before: {lst}")
                        sub_index = lst.index(sub) # get sublist index
                        sub += _sub # merge the two sublists together
                        lst[sub_index] = list(set(sub)) # remove the dupe
                        lst.remove(_sub) # remove the merged sublsit
                        merged = True # set flag
                        print(f"after: {lst}")
                    else:
                        pass
                else: # once the sublists are exhausted, skip checking the other values in the sublist
                    if merged: merged = False; break
        
        for sub in lst:
            all_items += sub
    return lst```

I'm not quite sure where im going wrong and if there's a better solution for it (im assuming there's something in itertools but im not familiar with it)

[zenith pagoda]

Hi, what is the time complexity of the code below? My initial thought is O(n) but I realize the min() function could affect the runtime but I'm not sure.

# strs = ["foo", "bar", "foobar", "barfoo"]
min_len = 0
for word in strs:
  min_len = min(min_len, len(word))

[agile sundial]

the min function does affect it

[void kettle]

Hey guys, does anyone know how to compare words from a list to words from a txt file? My purpose is to compare a sentence to a grammar and perform a leftmost derivation operation.

If anyone is familiar with how to implement left most derivations that'll help too

[zenith pagoda]

then what should be the time complexity of it?

[agile sundial]

well, what do you think?

@zenith pagoda

[zenith pagoda]

still O(n) because min() time complexity is O(1).

is that correct?

[agile sundial]

think about what operations min does

[zenith pagoda]

min compares two number only. We can do it in this form too:

if min_len < len(word):
  return min_len
else:
  return len(word)

And that is O(1)

[agile sundial]

ah shit I can't read

yeah it's O(n) my bad

[raven bison]

I would read the words in from the text file into a list then compare the two lists. Do you know the syntax for file io in python?

[raw zealot]

Hey,
I am an intermediate python programmer , but I only have experience of python
What's the best time for me to start learning algo and data structures

[flat sorrel]

Once you are comfortable with OOP

[hollow lichen]

Guys can anyone help me with this error

[flat sorrel]

You're already using TensorFlow 2

If you're using the latest version I think you can import feature_column directly from tf

Btw, if you're dealing with machine learning, you should ask in #data-science-and-ml

[fringe thistle]

TensorFlow Material?

[flat sorrel]

I don't really see TensorFlow being used outside of the machine learning field

[hollow lichen]

Ok thnx 😀

[hollow lichen]

Ohk

[void kettle]

I don't but I can look online

[void kettle]

Thank you for your help tho man

[pure terrace]

class Pool:

    def __init__(self):
        pass

    def to_dict(self) -> dict:
        data = {
            "_id": self._id,
            "choices": self.choices,
        }
        return data
my_new_pool = Pool()      
my_new_pool._id = 1
key = "1"
my_new_pool.choices = {}
my_new_pool['choices'][key] = 'value'
print(my_new_pool['choices'][key])
```It doesn't give me its value

[trim fiber]

my_new_pool.choices is not my_new_pool["choices"]

Try my_new_pool.to_dict()["choices"]

[pure terrace]

Roger that, I will try that thank you

[kindred coyote]

Let's say I have this problem: Input Specification: First Line: contains an integer, M (1 < M < 1 000 000) Next M lines: contains two integers For example: ```py

5
1 2
3 4
5 6
7 8
9 10
I know you can do this using this:py
m = input()
for i in range(m):
numbers = input()

[agile sundial]

how would you be able to reduce the complexity

[vocal gorge]

Time complexity? Definitely not, how'd you read numbers without reading them?

[agile sundial]

you have to read every integer, and to read it, you have to look at them

[kindred coyote]

also I have another questions

[vocal gorge]

also, you're missing a cast to int

[kindred coyote]

So i have this problem: ```
Problem Description
A new and upcoming artist has a unique way to create checkered patterns. The idea is to
use an M-by-N canvas which is initially entirely black. Then the artist repeatedly chooses
a row or column and runs their magic brush along the row or column. The brush changes
the colour of each cell in the row or column from black to gold or gold to black.
Given the artist’s choices, your job is to determine how much gold appears in the pattern
determined by these choices.

Input Specification
The first line of input will be a positive integer M. The second line of input will be a positive
integer N. The third line of input will be a positive integer K. The remaining input will be
K lines giving the choices made by the artist. Each of these lines will either be R followed
by a single space and then an integer which is a row number, or C followed by a single space
and then an integer which is a column number. Rows are numbered top down from 1 to M.
Columns are numbered left to right from 1 to N.

Output Specification
Output one non-negative integer which is equal to the number of cells that are gold in the
pattern determined by the artist’s choices.

And I have two pieces of code, but idk which one is more efficient

https://paste.pythondiscord.com/ziquvowoba.properties

[vocal gorge]

If you're not sure, profile it.

https://docs.python.org/3/library/profile.html#module-cProfile
https://docs.python.org/3/library/profile.html#instant-user-s-manual

[kindred coyote]

I have a questions

So on the first line of input are two numbers, N and M
The next M lines contain 3 numbers, X Y and Z
How would I generate an array in which the GCD (Greatest Common Divisor) of arr[(X-1)] and arr[(Y-1)] are equal to Z. Note that this array must fall true of all of the different M lines. For example: ```py
2 2 #2 is N, 2 is M
1 2 2 # X is 1, Y is 2, Z is 2
2 2 6 # X is 2, Y is 2, X is 6

[4,6] #The GCD of arr[X-1] (4) and arr[Y-1] (6) is 2 (Line 1)
#The GCD of arr[X-1] (6) and arr[Y-1] (6) is 6 (Line 2)

[cobalt forum]

https://stackoverflow.com/questions/66288335/make-an-increasing-array-while-modifying-the-array

pls see

if y'all could help

[sand kiln]

do anyone knows what go to spaces?

[fierce mantle]

what does that comment say?

[willow meteor]

hi all; what's the best way of storing info in this format, but if i want to be able to search efficiently with both the name or detail?

sorry for my quick whiteboard sketch

should i make 2 copies of the json, 1 for name and other for detail?

1 name can have multiple details and 1 detail can have multiple names

[glossy breach]

I'm not sure but I think you can try this greedy algorithm:
For each i from 1 -> n, arr[i - 1] is LCM of all Z in lines which X or Y equals to i + 1.

If the resulting array does not fit the criterias then it's probably impossible 🤔

[trim fiber]

What you did and what is the problem?

[rancid patio]

has anyone seen this problem before
Consider an array, a, of n distinct positive integers where the elements are sorted in ascending order. We want to find all the subsequences of a consisting of exactly m elements. For example, given array a = [1, 2, 3, 4], the subsequences consisting of m = 3 elements are {1, 2, 3}, {1, 2, 4}, {1, 3, 4}, and {2, 3, 4}. Once we have all of the m-element subsequences, we find the value of globalMaximum using the following pseudocode

for each subsequence, s, consisting of m elements {
    currentMinimum = 1018
    for each (x, y) pair of elements in subsequence s {
        absoluteDifference = abs(x - y)
        if absoluteDifference < currentMinimum {
            currentMinimum = absoluteDifference
        }
    }
    
    if currentMinimum > globalMaximum {
        globalMaximum = currentMinimum
    }
}```

i am not fully understanding the concept of global maximum

based on the example outputs provided

[idle ferry]

writing a programm for this exercice it's words guessing game

[trim fiber]

!rule 5

[halcyon plank]

Rules

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

[trim fiber]

As far as I understand globalMaximum is the biggest difference between two elements in all considered subsequences

[rancid patio]

which is what i believed, not sure why this is the result though

After the iteration on subsequence {1, 2, 3}, the value of globalMaximum is 1.
After the iteration on subsequence {1, 2, 4}, the value of globalMaximum is 1.
After the iteration on subsequence {1, 3, 4}, the value of globalMaximum is 1.
After the iteration on subsequence {2, 3, 4}, the value of globalMaximum is 1.
Thus, the function returns 1 as the answer.```

[trim fiber]

Oh, I am wrong

We are calculating currentMinimum so globalMaximum is the biggest of the smallest absolute difference between two elements

[rancid patio]

The subsequences of array a = [1, 2, 3, 4] consisting of m = 2 elements are {1, 2}, {1, 3}, {1, 4}, {2, 3}, {2, 4}, and {3, 4}.
After the iteration on the subsequence {1, 2}, the value of globalMaximum is 1.
After the iteration on the subsequence {1, 3}, the value of globalMaximum is 2.
After the iteration on the subsequence {1, 4}, the value of globalMaximum is 3.
After the iteration on the subsequence {2, 3}, the value of globalMaximum is 3.
After the iteration on the subsequence {2, 4}, the value of globalMaximum is 3.
After the iteration on the subsequence {3, 4}, the value of globalMaximum is 3.
Thus, the function returns 3 as the answer.```

here is another example

last one

The subsequences of array a = [1, 2, 4, 5, 8] consisting of m = 3 elements are {1, 2, 4}, {1, 2, 5}, {1, 2, 8}, {1, 4, 5}, {1, 4, 8}, {1, 5, 8}, {2, 4, 5}, {2, 4, 8}, {2, 5, 8}, and {4, 5, 8}.
After the iteration on the subsequence {1, 2, 4}, the value of globalMaximum is 1.
After the iteration on the subsequence {1, 2, 5}, the value of globalMaximum is 1.
After the iteration on the subsequence {1, 2, 8}, the value of globalMaximum is 1.
After the iteration on the subsequence {1, 4, 5}, the value of globalMaximum is 1.
After the iteration on the subsequence {1, 4, 8}, the value of globalMaximum is 3.
After the iteration on the subsequence {1, 5, 8}, the value of globalMaximum is 3.
After the iteration on the subsequence {2, 4, 5}, the value of globalMaximum is 3.
After the iteration on the subsequence {2, 4, 8}, the value of globalMaximum is 3.
After the iteration on the subsequence {2, 5, 8}, the value of globalMaximum is 3.
After the iteration on the subsequence {4, 5, 8}, the value of globalMaximum is 3.
Thus, the function returns 3 as the answer.```

[trim fiber]

Updated my message above, check it

[rancid patio]

sub sequence as in (1,2), (2,3) -> (1,2,3)?

[trim fiber]

No, it's like (1, 2, 3) with m = 2 then (1, 2), (2, 3), (1, 3) so every possible combination
https://www.wolframalpha.com/input/?i=n+choose+k

[night pewter]

hi y'all. I'm in search of deeper knowledge. by accident I wrote a condition which gets really good results, but it's obviously bogus, so I want understand what it actaully does. I know when accessing a panda dataframe viadataframe.loc[] "Logical Operators in Pandas are &, | and ~, and parentheses (...) " are important. And that you are actually generating a series which then gets used as an index.
This is the code I'm talking about:

        dataframe.loc[
            (
                (dataframe['ha_marubozu']) &
                (dataframe['smooth_ha_green']) & 
                (False) &  # WHAT DOES THIS DO?
                (dataframe['smooth_ha_green'].shift(2) != True) | 
                (dataframe['smooth_ha_green'].shift(3) != True) &                 
                (dataframe['volume'] > 0)  
            ),
            'buy'] = 1

Does (False) & just flip a column (before or after?). If I delete (False) & I actually get different results

[rancid patio]

@trim fiber thanks for the help

[trim fiber]

Your welcome

[night pewter]

I suspect it may have something to do with the bitwise |

[night pewter]

Ok, to answer my own question. Basically what it does, it negates everything that comes before (False) &. It' like I just deleted:

    (dataframe['ha_marubozu']) &
    (dataframe['smooth_ha_green']) & 

[rancid patio]

@trim fiber in example 2, are we comparing the differences between ([1,2) and (2,4) and since 2-1 < 4-2 the global maximum is 1

then do that for each ele

[trim fiber]

About which one are you talking?

[trim fiber]

This one?

[rancid patio]

yes that was the one i was referring to

really any example

[trim fiber]

Before first iteration we have globalMaximum = 0.
Then from subsequence {1, 2, 4} we get localMinimum = 1 then localMinimum > globalMaximum so globalMaximum = 1
Later next sequences {1, 2, 5}, {1, 2, 8} and {1, 4, 5} gives us localMinimum = 1 so we don't update globalMaximum.
In each other sequences we get:

• {1, 4, 8} gives 3 because 4 - 1 is less than 8 - 4 so globalMaximum is now 3;
• {1, 5, 8} gives 3 too;
• {2, 4, 5} gives 1 but 1 is less than current globalMaximum;
• {2, 4, 8} gives 1 too;
• {2, 5, 8} gives 3 so don't update because it's equal to globalMaximum;
• {4, 5, 8} gives 1 again.

[rancid patio]

@trim fiber thanks so much

[rancid patio]

last question @trim fiber why does - {2, 4, 5} gives 1 but 1 is less than current globalMaximum; give 1, looking at the example it is returning After the iteration on the subsequence {2, 4, 5}, the value of globalMaximum is 3

[fiery cosmos]

help idk whats wrong with my while loop

while phcid == True do:

phcid is a var

boolean

[vocal gorge]

do is wrong.

[fiery cosmos]

OH

sorry i forgot its not lua...

[vocal gorge]

Also, it'd fit more in a help channel or general 🙂

[fiery cosmos]

okay

where can i share my code?

[vocal gorge]

in a help channel, ideally

!paste if it's big

[halcyon plank]

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]

okay

[vocal gorge]

(see #❓｜how-to-get-help if you don't know how the channels work)

[fiery cosmos]

thank you

[drowsy minnow]

Does anyone have experience with Trie's? Attempting to convert this kinda brute force method into a trie instead. I was told it would be more efficient but I'm having a hard time understanding the concept entirely. If you get what I'm talking about, let me know and I'll show ya the whole algo question.

def removeDuplicates(str):
    return "".join(set(str))
def numKeypadSolutions(wordlist,keypads):
    a=[]
    for x in wordlist:
        x=removeDuplicates(x)
    for x in keypads:
        flag=True
        count=0
        for y in wordlist:
            if(x[0] not in y):
                continue
            for z in y:
                if(z not in x):
                    flag=False
                    break
            if(flag):
                count+=1
        a.append(count)
    return a
  
wordlist=['APPLE','PLEAS','PLEASE']
keypads=['AELWXYZ','AELPXYZ','AELPSXY','SAELPRT','XAEBKSY']
a=numKeypadSolutions(wordlist,keypads)
print(a)

[keen hearth]

Hey @small sage Do you still need help with your problem? Just reading up on that algorithm.

[small sage]

yes

i do

can u?

@keen hearth

I need help with Union Find

[keen hearth]

Alright 😄

So, it's the algorithm to union two sets in a disjoint set data structure that you need help with?

[glossy breach]

What's your problem with Union Find?

[oblique echo]

Hello algorithms experts, I have 2 questions about the following algorithm. What is the specific type of algorithm used in the sort() method, and how can I tell the complexity in Big O notation?

class Algorithm:
    """
    A class to represent an algorithm.

    ...
    Attributes
    ----------
    
    Methods
    -------
    sort()
        outputs a sorted list of integers

    """

    def sort(self, data, length): #(data, n):
        """ Outputs a sorted list of integers
        Parameters
        ----------
        data : list
            a collection of integers as a list

        length : integer
            an integer value representing the len() of the data list
        """
        
        if length == 1:
            print(data)
            return
        
        for i in range(length):
            self.sort(data, length - 1)
            if length % 2 == 0:
                data[i], data[length - 1] = data[length - 1], data[i]
            else:
                data[0], data[length - 1] = data[length - 1], data[0]

[agile sundial]

that sounds like a test question?

[oblique echo]

The test was to use it (it swaps numbers around so 1 2 becomes 2 1) and say what the Big O is. I just want to know what it is and how to even try to find the Big O

Just looking for some general guidance, not an answer

[agile sundial]

is it a test question?

[oblique echo]

It's part of a homework assignment to say what the complexity is in Big O.

[agile sundial]

ok, what do you think it is

[oblique echo]

It seems like quadratic time because it takes really long to run when I put in a lot of inputs

[agile sundial]

why isn't it cubic then

[oblique echo]

good point

can it have 2? because it would be constant if length was 1

[agile sundial]

it can't have two time complexities

and time complexity is based on how it changes, so it's not just about when the length is 1

[oblique echo]

understood, thank you

[dreamy arrow]

time complexity here you have (n) iterations for the first loop then for each time in that n you have to call the recursion which decrease size by 1 each time so it will call itself n times as well until it reaches the base case at length =1
so Time Complexity = n*n *(Condition)
Condition = O(1) Because its assignment

nn1 = n^2

nn1

nn1=n^2

[vocal gorge]

sort of an n-length list calls, n times, sort of an n-1-length list, and also does n O(1) operations.
So the recurrent equation for T(n) is:

T(n) = n T(n-1) + n

and T(1) is around n operations (it's a print)

[severe geyser]

Funny thing, i'm also learning about the BigO notation atm

[vocal gorge]

This recurrent equation is solved by approximately n!. So factorial complexity, if I didn't mess anything up.

way higher than O(n^2). @dreamy arrow

[severe geyser]

alright

[vocal gorge]

here's a plot of computation time vs the list's length

Same plot with logarithmic y axis. As you can see, time appears to be exponential with the list's length, but you can also see a slight curve upwards compared to the straight line approximation (orange line) - factorial complexity indeed.

[fast timber]

j

[noble leaf]

can I plz get help i dont understand this question based on the essay Look Away by Siri Hustvedt?
Hustvedt recounts a story about her daughter, Sophie’s, experience on the subway and the way in which a fellow passenger ‘broke the code’ of the “pretend-it-isn’t-happening law.” In doing so, Hustvedt argues, the man gave Sophie “a feeling of ordinary human solidarity.” Explain what she means by this and why she feels it’s so important.

[vocal gorge]

...how is that related to algorithms and data structures, or even programming at all?

[agile sundial]

use gpt3, duh @vocal gorge

[vocal gorge]

But that's #data-science-and-ml 😉

[agile sundial]

that's still an algorithm though

[rancid patio]

is there a way to dynamically use the len of a tuple to use in a for loop

for example if the length of the tuple == 2 then -> for x,y in tuple: and if the tuple len==3 then -> for x,y,z in tuple"

[agile sundial]

wait for pattern matching in 3.10 i guess lol

[proven creek]

Pretty sure a similar thing can be solved if you look into *args and **kwargs @rancid patio https://realpython.com/python-kwargs-and-args/

# sum_integers_args.py
def my_sum(*args):
    result = 0
    # Iterating over the Python args tuple
    for x in args:
        result += x
    return result

print(my_sum(1, 2, 3))

[agile sundial]

i don't see how that's useful here

[proven creek]

then i'm probably misunderstanding something

lol

[rancid patio]

this is what im doing

n = 2
x =list(combinations( [1,2,3,4], n))
gloabl = 0
local_min = 0
n = 2
for a, b in x:
    lm = findMinDiff((a,b),n)
    if lm > local_min:
        local_min= lm
local_min```

so n will obviously change, up the the length of the list

[proven creek]

mhm, and if you have a helper function which takes *args

you can deal with the varying amount of iterables

@agile sundial making me feel crazy but i'm pretty sure i'm making sense

[lean dome]

I think you are, too.

[proven creek]

🙏

[proven creek]

*args right?

[lean dome]

But that's overcomplicating it, I think

[proven creek]

ah, fair enough

[rancid patio]

    # Initialize difference as infinite 
    diff = 10**20
      
    # Find the min diff by comparing difference 
    # of all possible pairs in given array 
    for i in range(n-1): 
        for j in range(i+1,n): 
            if abs(arr[i]-arr[j]) < diff: 
                diff = abs(arr[i] - arr[j]) 
  
    # Return min diff 
    return diff```

[lean dome]

You can just do:

for t in x:
    lm = findMinDiff(t, n)
    ...

[agile sundial]

yeah, ^