Creating lists of lists in a pythonic way

Question

I\'m using a list of lists to store a matrix in python. I tried to initialise a 2x3 Zero matrix as follows.

mat=[[0]*2]*3

However, when I chang

Answer 1

What about:

m, n = 2, 3
>>> A = [[0]*m for _ in range(n)]
>>> A
[[0, 0], [0, 0], [0, 0]]
>>> A[0][0] = 1
[[1, 0], [0, 0], [0, 0]]

Aka List comprehension; from the docs:

List comprehensions provide a concise way to create lists 
without resorting to use of     
map(), filter() and/or lambda. 
The resulting list definition tends often to be clearer    
than lists built using those constructs.