排序（项目，lambda）有多个项目，一个反转

Question

我如何进行以下排序？

import re
list_of_strings=['hulu_delta_20150528.xml', 'hulu_delta_20150524', 
                 'playstation_full_20150529', 'hulu_full_20150528.xml']
sorted(list_of_strings, key=lambda x: (
    x[:3], 
    re.search(r'\d{8}',x).group() if re.search(r'\d{8}',x) else None,
    -x # How would this be done as a third criteria?
))

特别是，我如何按反向字母顺序排列项目作为第三个标准？最终结果应该是：

['hulu_delta_20150524', 'hulu_full_20150528.xml', 'hulu_delta_20150528.xml', 'playstation_full_20150529']

Answer 1

您可以比较项目的负序数值，以按字母顺序进行比较：

#  All hulu strings have same date 
>>> list_of_strings=['hulu_delta_20150528.xml', 'hulu_delta_20150524', 
                     'playstation_full_20150529', 'hulu_full_20150528.xml']
>>> files = sorted(list_of_strings, key=lambda x: (
    x[:3],
    re.search(r'\d{8}',x).group() if re.search(r'\d{8}', x) else None,
    [-ord(c) for c in x]
))
>>> files
['hulu_delta_20150524', 'hulu_full_20150528.xml', 'hulu_delta_20150528.xml', 'playstation_full_20150529']