python reversed(list)和list.sort(reverse = True)之间的区别 [英] python Difference between reversed(list) and list.sort(reverse=True)

问题描述

mylist = reversed(sorted(mylist))

vs

mylist = sorted(mylist, reverse=True)

为什么一个要比另一个要用?

Why would one be used over the other?

如何在多个列上进行稳定排序，例如

How about for a stable sort on multiple columns such as

mylist.sort(key=itemgetter(1))
mylist.sort(key=itemgetter(0))
mylist.reverse()

与

mylist.sort(key=itemgetter(1), reverse=True)
mylist.sort(key=itemgetter(0), reverse=True)

?

推荐答案

您准确地找到了 区别.由于 Timsort 是稳定的，因此反向排序与反向排序将使未排序元素以相反的顺序.

You have hit on exactly the difference. Since Timsort is stable, sorting on the reverse versus reversing the sort will leave the unsorted elements in reverse orders.

>>> s = ((2, 3, 4), (1, 2, 3), (1, 2, 2))
>>> sorted(s, key=operator.itemgetter(0, 1), reverse=True)
[(2, 3, 4), (1, 2, 3), (1, 2, 2)]
>>> list(reversed(sorted(s, key=operator.itemgetter(0, 1))))
[(2, 3, 4), (1, 2, 2), (1, 2, 3)]

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