获取列表的最后一个元素 [英] Getting the last element of a list

问题描述

在Python中，如何获取列表的最后一个元素?

In Python, how do you get the last element of a list?

推荐答案

some_list[-1]是最短和最Python化的语言.

some_list[-1] is the shortest and most Pythonic.

实际上，您可以使用此语法做更多的事情. some_list[-n]语法获取第n个倒数第二个元素.因此，some_list[-1]获取最后一个元素，some_list[-2]获取倒数第二个，依此类推，一直向下到some_list[-len(some_list)]，这将为您提供第一个元素.

In fact, you can do much more with this syntax. The some_list[-n] syntax gets the nth-to-last element. So some_list[-1] gets the last element, some_list[-2] gets the second to last, etc, all the way down to some_list[-len(some_list)], which gives you the first element.

您也可以通过这种方式设置列表元素.例如:

You can also set list elements in this way. For instance:

>>> some_list = [1, 2, 3]
>>> some_list[-1] = 5 # Set the last element
>>> some_list[-2] = 3 # Set the second to last element
>>> some_list
[1, 3, 5]

请注意，按索引获取列表项将引发 IndexError 如果期望的项目不存在.这意味着如果some_list为空，则some_list[-1]将引发异常，因为空列表不能包含最后一个元素.

Note that getting a list item by index will raise an IndexError if the expected item doesn't exist. This means that some_list[-1] will raise an exception if some_list is empty, because an empty list can't have a last element.

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