How to to read a matrix from a given file?

Question

I have a text file which contains matrix of N * M dimensions.

For example the input.txt file contains the following:

Answer 1

You should not write your csv parser, consider the csv module when reading such files and use the with statement to close after reading:

import csv

with open('input.txt') ad f:
    data = [map(int, row) for row in csv.reader(f)]