"Go" How to initialize a two-dimensional an array in Python?

Tag: Object res element note DDR because pre lang [1]

"Wrong:"

m=[[element] * numcols] * numrows

For example:

>>> m=[[' A '] * 2
>>> m
[[' A ', ' a ', ' a '], [' A ', ' a ', ' a ']]
>>> M[1][1]
A
>>> m[1][1]= ' B '
>>> m
[[' A ', ' b', ' a '], [' A ', ' B ', ' a ']]

Note: At this time m[0][1] has also been modified, because is * copying the address of the object (list), m[0][1] and m[1][1] reference to same object.

"Right:"

m = [[element for x in range(numcols)] for y in range(numrows)]
for example:

>>> m=[[' A ' for X in range (3)] for Y in range (2)]
>>> m
[[' A ', ' a ', ' a '], [' A ', ' a ', ' a ']]
>>> M[1][1]
A
>>> m[1][1]= ' B '
>>> m
[[' A ', ' a ', ' a '], [' A ', 'b', ' a ']]

"Go" How to initialize a two-dimensional an array in Python?