How to read numbers from file in Python

Question

I want to read numbers from a file into a two-dimensional array.

The file contents are as follows:

line containing w, h
h lines containing w integers separated with space
For example:

4 3
1 2 3 4
2 3 4 5
6 7 8 9

Answer 1

Assuming you don't have extraneous whitespace:

with open('file') as f:
    w, h = [int(x) for x in next(f).split()] # read first line
    array = []
    for line in f: # read rest of lines
        array.append([int(x) for x in line.split()])
 

You could condense the last for loop into a nested list comprehension:

with open('file') as f:
    w, h = [int(x) for x in next(f).split()]
    array = [[int(x) for x in line.split()] for line in f]

Hope this will help!

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Thank!