在python中使用*运算符创建列表

Question

Why does [0] * 5 create a list [0, 0, 0, 0, 0] , rather than [[0], [0], [0], [0], [0]] ?

Doesn't the * operator duplicate [0] 5 times resulting in [[0], [0], [0], [0], [0]] ?

Answer 1

Just like math:

[0] * 5 = [0] + [0] + [0] + [0] + [0] , which is [0, 0, 0, 0, 0] .

I think people would be more surprised if [0] + [0] suddenly became [[0], [0]] .

For strings, tuples, and lists, + is an append operator. This multiplication holds true for all of them.

Answer 2

阅读序列类型的 Python 文档似乎是因为[0] * 5是[0] + [0] + [0] + [0] + [0]的简写（就像乘法在数学中是加法；当“乘”列表时，它的工作原理相同）。

Answer 3

不，它将元素相乘并且 [0] 列表（就像数学集一样）有一个元素 0，而不是 [[0]]。

Answer 4

Use statement below to create [[0], [0], [0], [0], [0]]:

[[0]*1]*5

Note that the list you've mentioned above is a 2d list, so you must use * operator in right way. It means your list has 5 rows and 1 column.

Below is the real result: enter image description here