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

Here's some minimal example that extends 2d list of lists:

my_list = [ [  [1] for x in range(4) ] for j in range(2) ]
print('initial list is ', my_list)
my_list[0][1].append(9)
print('list after extension is ', my_list)

and the results are

initial list is  [[[1], [1], [1], [1]], [[1], [1], [1], [1]]]
list after extension is  [[[1], [1, 9], [1], [1]], [[1], [1], [1], [1]]]

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