1"""isort/natural.py. 2 3Enables sorting strings that contain numbers naturally 4 5usage: 6 natural.nsorted(list) 7 8Copyright (C) 2013 Timothy Edmund Crosley 9 10Implementation originally from @HappyLeapSecond stack overflow user in response to: 11 https://stackoverflow.com/questions/5967500/how-to-correctly-sort-a-string-with-a-number-inside 12 13Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated 14documentation files (the "Software"), to deal in the Software without restriction, including without limitation 15the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and 16to permit persons to whom the Software is furnished to do so, subject to the following conditions: 17 18The above copyright notice and this permission notice shall be included in all copies or 19substantial portions of the Software. 20 21THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 22TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 23THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 24CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 25OTHER DEALINGS IN THE SOFTWARE. 26 27""" 28import re 29 30 31def _atoi(text): 32 return int(text) if text.isdigit() else text 33 34 35def _natural_keys(text): 36 return [_atoi(c) for c in re.split(r'(\d+)', text)] 37 38 39def nsorted(to_sort, key=None): 40 """Returns a naturally sorted list""" 41 if key is None: 42 key_callback = _natural_keys 43 else: 44 def key_callback(item): 45 return _natural_keys(key(item)) 46 47 return sorted(to_sort, key=key_callback) 48