remove() removing from all items in list

Question

.remove() has some behavior I don't understand.

x = [[1,2,3]]*3
x[0].remove(1)

then x becomes [[2, 3], [2, 3], [2, 3]].

Why does this happen, and how can I fix this? I want 1 removed from the first list only.

@thefourtheye your answer was helpful, you should undelete it — qwr, Feb 14 '14 at 05:45
@thefourtheye, don't be discouraged by the odd downvote. Sometimes the downvoter just might not know as much as they think they do. If only they'd give a reason, they might learn something new... — John La Rooy, Feb 14 '14 at 06:32

score 4 · Answer 1 · edited Feb 14 '14 at 05:36

4

If you created x something like this:

a = [1,2,3]
x = [a,a,a]

Then the elements of x are actually the same object, and changing one of them causes the change to be reflected in all of them.

edited Feb 14 '14 at 05:36

mishik

answered Feb 14 '14 at 05:34

ooga

1 Answers1