Questions tagged [python]
Programming questions are off-topic here. Do not ask questions about how to write code in Python. However, conceptual questions about computer science are more appropriate. See our help center for the scope of this site.
207
questions
-3
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0
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13
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python django- adding a like function button [closed]
I am trying to add a like function to my blog, but I keep getting this error.
0
votes
1
answer
29
views
What is the practical use of list.clear() method in Python?
I was wondering if there is a reason behind clearing all the values in a list and reusing it, as opposed to deleting the list and creating a new one. Are there any practical advantages of using ...
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-4
votes
0
answers
36
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Maximum possible coincidences? Python code please [closed]
Given $M = [0,4,8,15]$ as points on a real line place 2 points $C_1$, $C_2$ on the line according to the following conditions
Both $C_1$ and $C_2$ cannot be placed at 0 or 15.
Distance between $C_1$ ...
0
votes
0
answers
32
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Trying to model HIV using cellular automaton but can't replicate the results of some paper
There is this paper in which HIV is modelled using cellular automaton. I am trying to replicate this work but I am not getting the same results as the authors. In this paper the authors describe the ...
- 1
1
vote
0
answers
12
views
Auxiliary Space Complexity of Dictionaries whose Keys are Iterables of Variable Size
Recently, I began delving into complexity analysis with dictionaries. More specifically, I have been looking at auxiliary space complexity. For the most part, this type of analysis has been ...
- 11
0
votes
0
answers
37
views
fast estimation of the amount of unique combinations
Let's say I have a set of two columns - Name, Surname. I have a list of possible values for
Name -> Jacob, John
Surname -> Mayerson, Kindle.
I want to generate a set of unique combinations for ...
- 125
0
votes
1
answer
34
views
Should I concatenate three lists together or use two separate while loops in Python? Which option offers a better runtime complexity?
In the context of adding sparse polynomials, you have two alternative approaches to combine the terms from two separate polynomials. One option is to use the line of code ...
0
votes
1
answer
85
views
Why boolean value in Python is 24/28 bytes?
What is the reason for this behavior? Usually, in other programming languages, it is either 4/8 bytes, if I am correct.
- 19
0
votes
1
answer
29
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compute the intersection of two polytopes and it's corner points
I am looking for a method in python/matlab to calculate the corner points of polytope which is an intersection of a polytope with half spaces.
I have a polytope P1 of the form
-1<= x0 <= 1
-1&...
- 21
1
vote
0
answers
51
views
Diffucuty in understanding code after a recursive call
This is an example algorithm of a recursive insertion sort I'm trying to understand. I've have tried understanding this with
the help of print statements (which I've commented).
...
- 11
0
votes
1
answer
23
views
Combining chunks on an infinite grid into regions
I am working on an floorplan application where I save elements on an infinite grid in a sparse manner. Specifically, I have the following Python class representing a sparse grid (basically a ...
- 103
0
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0
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21
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Approach for the fake data generator that needs to maintain an order and referential integrity
I have a Python data generator capable of generating SQL-like relational data with primary and foreign key relationships, composite keys, and partial keys. Currently, I store this data in-memory using ...
- 125
0
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0
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53
views
A practical issue in the code of HackerRank Restaurant problem
Problem Statement
Martha is interviewing at Subway. One of the rounds of the interview requires her to cut a bread of size $\ell \times b$ into smaller identical pieces such that each piece is a ...
- 101
-2
votes
4
answers
109
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Can halting problem solved by soft computation?
As far as I know, the halting problem means we can't create a program that checks whether another program is stuck or halt based on given input. This means, the program expects two inputs and one ...
-1
votes
1
answer
114
views
Design an algorithm to predict words based on a skeleton from a given dictionary
I'm working on an algorithm which is permitted to use a training set of approximately 250,000 dictionary words.
I have built and providing here with a basic, working algorithm. This algorithm will ...
- 99
1
vote
1
answer
81
views
Sympy does not recognise when two partial derivatives happen to be equal
I am trying to find the first and second-order partial derivatives of a function of four variables $S$ using pythons symbolic math package sympy.
The issue is that sympy does not automatically see ...
- 11
-1
votes
1
answer
52
views
Detecting if an object reached target points
I have an object that is moving towards target points and I want to determine when it will reach or pass through them. I receive points in real time, which represent the current position of the object....
- 99
0
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0
answers
66
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Create a simple Neural Network of n layers in python from scratch with numpy to solve XOR example problem using Batch Gradient Descent
I'm a young programmer that was interested by machine learning. I watched videos and read articles about the theory behind simple neural networks. However, I can't manage to set it up correctly. I've ...
- 1
0
votes
2
answers
89
views
Why does Python behave so absurdly when dealing with numbers with decimal points?
r1 and r2 both are assigned 0.05 initially. If r1 is incremented by 0.01 in this way "r1 = r1 +0.01" we have 0.060000000000000005 as answer not 0.06.
- 11
0
votes
0
answers
5
views
Reproducible research (published papers) about e-commerce or fashion
I am looking for reproducible research (published papers) about e-commerce and/or fashion which deals with exploratory data analysis, hypothesis testing and regression or ANOVA. This reproducible ...
- 1
0
votes
3
answers
72
views
Number of islands
In the counting number of islands problem, I noticed that one of the solution from internet is as follows
...
- 103
0
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0
answers
14
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Python | Normalized Vector Based Player Controller
I recently started writing a 3D Engine using the Math Library, and PyGame for Graphics. I've made a simple demo scene, but I would like to make a "First-Person" like Camera Controller.
I've ...
0
votes
2
answers
35
views
Discarding lists of same elements
Suppose, I have a list of lists where multiple lists can have same elements. In my final output, I just want one list with the same element. An example is the following:
Input: A=[[1,2,0], [0,1,2], [2,...
0
votes
2
answers
75
views
Speeding up an array search for duplicate
I was tasked with writing a function that finds the value of an element that is the first duplicate in an array to be encountered. For the array
[2, 1, 3, 5, 3, 2]
...
- 101
0
votes
1
answer
97
views
Can somebody explain to me the concept of mutability with respect to a NumPy array?
From the NumPy documentation:
"NumPy arrays have a fixed size at creation, unlike Python lists (which can grow dynamically). Changing the size of an ndarray will create a new array and delete ...
- 101
11
votes
5
answers
3k
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Does an algorithm's space complexity include input?
Consider the Kadane's algorithm for finding maximum subarray within an array:
...
- 275
0
votes
1
answer
42
views
How sparsity term in loss function for sparse autoencoder is making hidden units inactive?
I am working on a Sparse Autoencoder but Andrew NG's notes are hard to understand.
My question is about the following equation: Loss Function.
In sparse autoencoder, the goal is to inactive some ...
1
vote
1
answer
35
views
Finding all zero sums of length m and checking for zero subsums on an abelian group (generalization of the sub sum problem?)
Let $G$ be an abelian group. We say that $G$ has property $V_n$ if for every $m > n$ and a list $L\subset G$ of $m$ elements s.t. $\sum_{g\in L}g=0$ there is a proper subset $\emptyset\neq L'\...
1
vote
1
answer
54
views
Having a 2D matrix with three typed elements, how to efficiently cover one of the types and NOT cover the other one?
I have a matrix with three possible elements: A, B and C. The size of the matrix could be a maximum of 15x16.
$$
\begin{bmatrix}
A & A & C & A\\
A & C & B & C\\
A & C & ...
- 111
1
vote
1
answer
115
views
How can I convert the pseudo-code that solves maximum subarray problem to Python code?
I'm reading Algorithm Design and Application, by Michael T. Goodrich and Robert Tamassia, and sometimes the pseudo-code in this book doesn't make sense at all.
At chapter one they show us 3 solutions ...
- 135
0
votes
1
answer
101
views
Finding whether a point lies on the boundary of an geometrical object or not?
Suppose I have the mesh of an geometrical object (Interval in 1d, Region in 2d, Volume in 3d). How can I find out whether a point lies on its boundary or not?
I am looking for algorithms with ...
- 111
0
votes
1
answer
80
views
Design an algorithm to calculate stock prices on a given day
Given a list of lists containing tuples in sorted(by day) order find and print the total number of stock units owned for every day that occurs at least once.
...
- 99
2
votes
4
answers
114
views
Algorithm that finds 4 "O"s or 4 "X"s on a diagonal, horizontal, or vertical
My algorithm homework revolves around matching 4 "O"'s or 4 "X"'s on a diagonal, horizontal, or vertical. ...
- 123
1
vote
2
answers
388
views
Is the complexity of this two-sum binary search algorithm $O(\lg n)$ or $O((\lg n)^2)$?
This algorithm solves the Two-Sum problem$^1$ assuming that the input array/list is sorted.
...
- 115
1
vote
0
answers
35
views
Long and short memory in reinforcement learning Connect 4 AI
I'm writing an AI based on reinforcement learning to play Connect 4. That's my second bot and attempt to RNN and AI (first was copy a code of snake RNN AI from youtube) and I'm looking for some ...
- 11
0
votes
1
answer
239
views
Finding a Hamiltonian Cycle in a directed graph - graph problem
$N$ towns are given, which we can get to by passing through the northern and southern gates. If you enter a town through a gate, you have to use another gate to leave the town. The merchant would like ...
- 71
3
votes
2
answers
685
views
Number of Inversions found in Selection sort vs Exchange sort
Exchange sort is similar to selection sort, just swaps "overly eagerly" instead of finding the minimum and doing only one swap. And the swaps affect how often the ...
- 483
0
votes
2
answers
1k
views
Dynamic Programming - Difficult Jumping Frog Problem
Given a set of $n$ stones, arranged in a row at equal distances from each other. The stones are numbered from $0$ to $n-1$. A frog that is on stone number $0$ has to get to stone number $n-1$.
A jump ...
- 71
-5
votes
1
answer
511
views
Implementing Flajolet–Martin algorithm in Python
I am stuck on what to do.
I am trying to create a simple implementation of the Flajolet–Martin algorithm using Python. The stream will be the contents of a text file and you will produce an ...
0
votes
1
answer
200
views
Is it faster to use Counting Sort to lexicographically sort characters in a word in Python?
Assuming I have very long words, is it worth it to use Counting Sort with its memory overhead to achieve linear time complexity?
I wrote a Python function that sorts the characters in a given string ...
- 1
0
votes
0
answers
192
views
render = font.render(text, 1, (0, 0, 0)) pygame.error: Library not initialized
the error im receiving is : file "/home/lucas/python/cargame/utils.py", line 17, in blit_text_center
render = font.render(text, 1, (0, 0, 0))
pygame.error: Library not initialized
the ...
- 1
3
votes
1
answer
142
views
Using pre-,post-, and in-order indexes to find information about a Binary Search Tree
Recently I have been studying ways of traversing a BST (in python), and have collided with the terms pre-order, post-order and in-order.
I believe that I understood the three terms pretty well, and ...
- 189
2
votes
2
answers
648
views
Doubt about computing running time / time complexity of a function in Python
I am learning about time complexity now, and I am working with BST (Binary Search Trees).
This question needs some context and this is a follow up post to this post. Basically, I would like to compute ...
- 189
2
votes
1
answer
63
views
Which approach of mine for an algorithm upper bound is correct?
Say we have this algorithm in Python.
...
1
vote
1
answer
147
views
When to stop training a back propagation algorithm based on the MSE?
I have a fully connected neural network that consists of 3 inputs + bias, 4 neuron hidden layer, and 2 layer output, I am using the sigmoid activation function on the hidden layer only and use the ...
- 11
1
vote
0
answers
29
views
What Data Structure works best for this problem?
I have 2 sets of atmost 25000 4-tuples. Currently, I am storing them as 2 lists of 4-tuples A and B.
I have to perform the following computation for each of the combinations of A and B.
...
- 11
1
vote
2
answers
261
views
Find the spanning tree minimizing the backtracking in an unweighted graph
I am working with undirected unweighted graphs, and I am searching for an algorithm that gives me a spanning tree minimizing the number of moves to visit every nodes.
For example, given this graph :
...
- 121
1
vote
0
answers
27
views
Multimodal machine learning dataset fine tuning for binary classification problem
Hello i am new to machine learning, i am working on a multimodal dataset, basically memes dataset, The data consists of an image and an overlay text, i have no clue how to feed a model both of the ...
0
votes
0
answers
57
views
Why is Python erasing all data in my text file?
I am having trouble understanding what's going on. I have just been introduced to the open() and close() commands in Python. I have a code that is very similar to the code below:
...
- 1
1
vote
1
answer
188
views
Efficient sorting an array generated from random distribution
I need to sort an array of n real numbers that was randomly generated in this way:
I have a given set of k closed intervals: [a1,b1],[a2,b2],...,[ak,bk] whose beginning and end are natural numbers. ...
- 71