Tagged Questions

0
votes
1answer
23 views

Array update anomaly in Python

I wrote the following code in python. Within checkd, when I update d[ii][jj], it seems as if the compiler takes its own liberties and makes all the following column entries to 1. Code: def ...
1
vote
3answers
57 views

2d array structure python

I am taking a python class and have no experience in python. The instructor only teaches documentation and refuses to give code examples. I understand C++ but I'm getting very frustrated with python ...
9
votes
4answers
174 views

Sum between pairs of indices in 2d array

Sorry, I do not know the protocol for re-asking a question if it doesn't get an answer. This question was asked a few months ago here: Numpy sum between pairs of indices in 2d array I have a 2-d ...
2
votes
2answers
62 views

How to create a Numpy 2d array with equal difference between rows?

How can I create a (48,64) Numpy array like this: i, i, i, .....,i i+0.1, i+0.1,..........,i+0.1 i+0.2, i+0.2,..........,i+0.2 . . . . i+6.3, i+6.3,..........,i+6.3 0.1 is the fixed ...
1
vote
1answer
167 views

Numpy sum between pairs of indices in 2d array

I have a 2-d numpy array (MxN) and two more 1-d arrays (Mx1) that represent starting and ending indices for each row of the 2-d array that I'd like to sum over. I'm looking for the most efficient way ...
0
votes
2answers
37 views

Inserting a new line in a 2D matrix

I have two functions that I can use to make an array: def makelist(size): list = [] for i in range(size): list = list + [None] return list def ...
1
vote
4answers
171 views

Python - getting values from 2d arrays

I have a 2d array: [[], ['shotgun', 'weapon'], ['pistol', 'weapon'], ['cheesecake', 'food'], []] How do I call a value from it? For example I want to print (name + " " + type) and get shotgun ...
0
votes
2answers
237 views

finding diagonal numbers

So I have this array here: t = [[8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8], [49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0], ...
2
votes
3answers
274 views

Manipulating indices to 2d numpy array

I can index a 2d numpy array with a tuple or even a list of tuples a = numpy.array([[1,2],[3,4]]) i = [(0,1),(1,0)] # edit: bad example, should have taken [(0,1),(0,1)] print a[i[0]], a[i] (Gives 2 ...
0
votes
3answers
247 views

Reducing duplicates in Python list of lists

I am writing a program that reads in a number of files and then indexes the terms in them. I am able to read in the files into a 2d array (list) in python, but then I need to remove the duplicates in ...
2
votes
1answer
2k views

2D array plotting in matplotlib

I was trying to plot a 2D array vs a 1D array with pyplot. I can do that with no problems and columns in the 2D array are treated like two different sets of Y datas, which is what i want. What i don't ...
3
votes
1answer
2k views

numpy - 2d array indexing

According to docs numpy's default behaviour is to index arrays first by rows then by columns: a = numpy.arange(6).reshape(3,2) [[0 1] [2 3] [4 5]] print a[0][1] # is 1 I want to index the array ...
1
vote
1answer
85 views

What's going on here? Repeating rows in random list of lists

I expected to get a grid of unique random numbers. Instead each row is the same sequence of numbers. What's going on here? from pprint import pprint from random import random nrows, ncols = 5, 5 ...
4
votes
5answers
2k views

Python - best way to set a column in a 2d array to a specific value

I have a 2d array, I would like to set a column to a particular value, my code is below. Is this the best way in python? rows = 5 cols = 10 data = (rows * cols) *[0] val = 10 set_col = 5 for row in ...
8
votes
7answers
604 views

What is meant by 2D array support?

I read that Python does not actually support 2D arrays but rather an array of an array. I understand the array of an array thing but what does it mean by supporting 2D arrays? In C a 2D array is ...
1
vote
4answers
1k views

Is there a Python module/recipe (not numpy) for 2d arrays for small games

I am writing some small games in Python with Pygame & Pyglet as hobby projects. A class for 2D array would be very handy. I use py2exe to send the games to relatives/friends and numpy is just ...