Suppose I do the following:
>>> l = [[]]*2
>>> l
[[], []]
>>> l[0].append(1)
>>> l
[[1], [1]]
Why does 1 get appended to both lists?
Suppose I do the following: >>> l = [[]]*2 >>> l [[], []] >>>
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Suppose I do the following:
>>> l = [[]]*2
>>> l
[[], []]
>>> l[0].append(1)
>>> l
[[1], [1]]
Why does 1 get appended to both lists?
[[]]*2is a list of two references to the same list. You are appending to it and then seeing it twice.