如何正确对里面有数字的字符串进行排序? [英] How to correctly sort a string with a number inside?

问题描述

我有一个包含数字的字符串列表，但找不到对它们进行排序的好方法.
例如我得到这样的东西:

I have a list of strings containing numbers and I cannot find a good way to sort them.
For example I get something like this:

something1
something12
something17
something2
something25
something29

使用 sort() 方法.

我知道我可能需要以某种方式提取数字然后对列表进行排序，但我不知道如何以最简单的方式进行.

I know that I probably need to extract the numbers somehow and then sort the list but I have no idea how to do it in the most simple way.

推荐答案

也许您正在寻找 human排序(也称为自然排序):

Perhaps you are looking for human sorting (also known as natural sorting):

import re

def atoi(text):
    return int(text) if text.isdigit() else text

def natural_keys(text):
    '''
    alist.sort(key=natural_keys) sorts in human order
    http://nedbatchelder.com/blog/200712/human_sorting.html
    (See Toothy's implementation in the comments)
    '''
    return [ atoi(c) for c in re.split(r'(d+)', text) ]

alist=[
    "something1",
    "something12",
    "something17",
    "something2",
    "something25",
    "something29"]

alist.sort(key=natural_keys)
print(alist)

收益

['something1', 'something2', 'something12', 'something17', 'something25', 'something29']

附注.我已经改变了我的答案，以使用 Toothy 的自然排序实现(发表在评论中 here) 因为它比我原来的答案快得多.

PS. I've changed my answer to use Toothy's implementation of natural sorting (posted in the comments here) since it is significantly faster than my original answer.

如果您希望使用浮点数对文本进行排序，那么您需要将正则表达式从匹配整数的正则表达式(即 (d+))更改为 匹配浮点数的正则表达式:

If you wish to sort text with floats, then you'll need to change the regex from one that matches ints (i.e. (d+)) to a regex that matches floats:

import re

def atof(text):
    try:
        retval = float(text)
    except ValueError:
        retval = text
    return retval

def natural_keys(text):
    '''
    alist.sort(key=natural_keys) sorts in human order
    http://nedbatchelder.com/blog/200712/human_sorting.html
    (See Toothy's implementation in the comments)
    float regex comes from https://stackoverflow.com/a/12643073/190597
    '''
    return [ atof(c) for c in re.split(r'[+-]?([0-9]+(?:[.][0-9]*)?|[.][0-9]+)', text) ]

alist=[
    "something1",
    "something2",
    "something1.0",
    "something1.25",
    "something1.105"]

alist.sort(key=natural_keys)
print(alist)

收益

['something1', 'something1.0', 'something1.105', 'something1.25', 'something2']

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