我有以下列表:
['pt=media:song', 'class=song', 'object=mp3']
['class=text','pt=transaction:email', 'object=email']
['category=where','pt=text:where','class:question']
['object:mp4','class=movie', 'pt=media:movie']
我想对它们进行排序,以便我始终首先从"pt="
开始,其余的按字母顺序排序。
所以结果将是:
['pt=media:song','class=song', 'object=mp3']
['pt=transaction:email','class=text', 'object=email']
['pt=text:where','category=where','class:question']
['pt=media:movie','class=movie','object:mp4']
我该怎么做?
答案 0 :(得分:5)
每个项目返回一个元组:
sorted(yourlist, key=lambda x: (not x.startswith('pt='), x))
这将首先排序以pt=
开头的任何值(False
之前的True
排序),任何其他值按字典顺序排序(这意味着应用于文本时按字母顺序排列)
演示:
>>> samples = [
... ['pt=media:song','class=song', 'object=mp3'],
... ['class=text','pt=transaction:email', 'object=email'],
... ['category=where','pt=text:where','class:question'],
... ['object:mp4','class=movie', 'pt=media:movie'],
... ]
>>> for sample in samples:
... print sorted(sample, key=lambda x: (not x.startswith('pt='), x))
...
['pt=media:song', 'class=song', 'object=mp3']
['pt=transaction:email', 'class=text', 'object=email']
['pt=text:where', 'category=where', 'class:question']
['pt=media:movie', 'class=movie', 'object:mp4']