如何清空列表? [英] How to empty a list?

问题描述

以这种方式清空列表似乎很肮脏":

It seems so "dirty" emptying a list in this way:

while len(alist) > 0 : alist.pop()

是否存在明确的方法?

推荐答案

这实际上是从列表中删除内容，但不会用新的空列表替换旧标签:

This actually removes the contents from the list, but doesn't replace the old label with a new empty list:

del lst[:]

这是一个例子:

lst1 = [1, 2, 3]
lst2 = lst1
del lst1[:]
print(lst2)

出于完整性考虑，切片分配具有相同的效果:

For the sake of completeness, the slice assignment has the same effect:

lst[:] = []

它也可以用于缩小列表的一部分，同时替换一部分(但这超出了问题的范围).

It can also be used to shrink a part of the list while replacing a part at the same time (but that is out of the scope of the question).

请注意，执行lst = []不会清空列表，只是创建一个新对象并将其绑定到变量lst，但是旧列表仍将具有相同的元素，并且如果具有其他元素，效果将显而易见.变量绑定.

Note that doing lst = [] does not empty the list, just creates a new object and binds it to the variable lst, but the old list will still have the same elements, and effect will be apparent if it had other variable bindings.

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