2d array of lists in python

Question

I am trying to create a 2d matrix so that each cell contains a list of strings. Matrix dimensions are known before the creation and I need to have access to any element from

Answer 1

You can either do it with the basic:

matrix = [
   [["s1","s2"], ["s3"]],
   [["s4"], ["s5"]]
]

or you can do it very genericially

from collections import defaultdict
m = defaultdict(lambda  : defaultdict(list))
m[0][0].append('s1')

In the defaultdict case you have a arbitrary matrix that you can use, any size and all the elements are arrays, to be manipulated accordingly.