如何按字符串长度和字母顺序排序? [英] how to sort by length of string followed by alphabetical order?

问题描述

我目前是python的新手，并且陷入了这个问题，似乎找不到正确的答案.

I'm currently new to python and got stuck at this question, can't seem to find the proper answer.

问题:给出一个单词列表，以长度顺序(从最长到最短)返回具有相同单词的列表，第二个排序标准应为字母顺序.提示:您需要考虑两个功能.

question:Given a list of words, return a list with the same words in order of length (longest to shortest), the second sort criteria should be alphabetical. Hint: you need think of two functions.

这是我到目前为止所拥有的:

This is what I have so far:

def bylength(word1,word2):
    return len(word2)-len(word1)

def sortlist(a):
    a.sort(cmp=bylength)
    return a

它按长度排序，但是我不知道如何将第二个标准应用于这种排序，即按字母降序.

it sorts by length but I don't know how to apply the second criteria to this sort, which is by alphabetical descending.

推荐答案

您可以按照以下两个步骤进行操作:

You can do it in two steps like this:

the_list.sort() # sorts normally by alphabetical order
the_list.sort(key=len, reverse=True) # sorts by descending length

Python的排序是稳定的，这意味着当长度相等时，按长度对列表进行排序会使元素按字母顺序排列.

Python's sort is stable, which means that sorting the list by length leaves the elements in alphabetical order when the length is equal.

您也可以这样:

the_list.sort(key=lambda item: (-len(item), item))

通常，您不需要cmp，甚至在Python3中将其删除. key更易于使用.

Generally you never need cmp, it was even removed in Python3. key is much easier to use.

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