Python size by size matrix that allows input and returns list of lists elements

Question

I'm trying to create an identity matrix that accepts input and returns an identity matrix(list or lists) of size by size, with only 1's and 0's without using numpy.

So if the user inputs: >>>matrix(4), the output should be: [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]

So far I've setup my list comprehension like this:matrix = [[0 for _ in range(3)] for _ in range(3)]

Any suggestions on how to setup my comprehension would be appreciated.

question from:https://stackoverflow.com/questions/65922346/python-size-by-size-matrix-that-allows-input-and-returns-list-of-lists-elements

Answer 1

Can cast a bool to an int to quickly get either a 0 or 1

def matrix(N):
    return [[int(col == row) for col in range(N)] for row in range(N)]