From http://nedbatchelder.com/blog/200712/human_sorting.html

natural_sort.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
# From http://nedbatchelder.com/blog/200712/human_sorting.html

import re


def tryint(s):
    try:
        return int(s)
    except:
        return s


def alphanum_key(s):
    """ Turn a string into a list of string and number chunks.
        "z23a" -> ["z", 23, "a"]
    """

    return [tryint(c) for c in re.split('([0-9]+)', s)]


def sort_nicely(l):
    """ Sort the given list in the way that humans expect.
    """

    l.sort(key=alphanum_key)

Formatted with http://www.tutorialspoint.com/online_python_formatter.htm

I wonder whether performance would improve if the regular expression were precompiled and reused.

Compare to Dave Koelle's Alphanum algorithm (If the site is down, use the archive.org copy)

See the comments from the article about:

• using groupby() to avoid regex
• ignoring case or this one
• simpler regex
• avoid exception-handling and a single-function style