如何在包含数字和字母的列表上的python中进行数字反向排序 [英] How to do a numeric reverse sort in python on a list which contains numbers and letters

问题描述

我的列表是这样的:

10.987|first sentence
13.87|second sentence
9.098|third sentence

如果我做类似的事情:

for x in my_list:
    sorted(my_list, reverse=True)

我在逻辑上得到:

9.098|third sentence
13.87|second sentence
10.987|first sentence

这是因为它没有被解释为数字，但是我无法将整个字符串转换为浮点数.我想要的是第一部分的数字排序:

This is because it is not interpreted as a number but I can't convert the whole string to a float. What I want is a numeric sort of the first part:

13.87|second sentence
10.987|first sentence
9.098|third sentence

我尝试使用itemgetter，但似乎找不到我想要的东西.在bash中，可以很容易地用

I tried using itemgetter but I can't seem to find exactly what I am looking for. In bash this can easily be solved with

sort -k

在python中有等同的功能吗?

Is there an equivalente to do this in python?

推荐答案

这是一种方法.

lst = ['10.987|first sentence',
       '13.87|second sentence',
       '9.098|third sentence']

res = sorted(lst, key=lambda x: -float(x.split('|')[0]))

结果

['13.87|second sentence',
 '10.987|first sentence',
 '9.098|third sentence']

说明

• sorted带有参数key，该参数允许您指定要在其上进行排序的自定义(lambda)函数.
• lambda函数用"|"分隔并提取第一部分以获取数字分量.
• 要进行数字排序，我们转换为float，最后求和以确保降序.
• 可以使用reverse=True参数代替否定符.

• sorted takes an argument key which allows you to specify a custom (lambda) function on which to sort.
• The lambda function splits by "|" and extracts the first part to get the numeric component.
• To sort numerically, we convert to float and finally negate to ensure descending order.
• Instead of negation, reverse=True argument may be used.

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