分配list [：] = […]时冒号在Python中做什么？

分配list [：] = […]时冒号在Python中做什么？

此语法是切片分配。一片

[:]

意味着整个列表。

nums[:] =

和之间的区别在于

nums=

后者不会替换原始列表中的元素。当有两个引用列表时，这是可见的

>>> original = [1, 2, 3]>>> other = original>>> original[:] = [0, 0] # changes the contents of the list that both   # original and other refer to >>> other # see below, now you can see the change through other[0, 0]

要查看差异，只需

[:]

从上面的分配中删除。

>>> original = [1, 2, 3]>>> other = original>>> original = [0, 0] # original now refers to a different list than other>>> other # other remains the same[1, 2, 3]

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从字面上看，如果

list

是变量名而不是内建函数，则将问题的标题替换为省略号

>>> list = [1,2,3,4]>>> list[:] = [...]>>> list[Ellipsis]