一行代码python list 去重

之前看到的的方法都是利用集合

keys = ['a', 'a', 'v', 'c', 'b', 'v', 'b']

list(set(keys))

Out: ['b', 'v', 'a', 'c']

问题：会导致去重之后list乱序.

 

注意到Python3 中dict默认是ordereddict 可以利用这一特性对list去重并保持原来的顺序

dct = {k:None for k in keys}

dct
Out: {'a': None, 'v': None, 'c': None, 'b': None}


list(dct) 
Out: ['a', 'v', 'c', 'b']

from itertools import zip_longest

dct = dict(zip_longest(keys, []))
dct
Out: {'a': None, 'v': None, 'c': None, 'b': None}

list(dct)
Out: ['a', 'v', 'c', 'b']

dct = dict.fromkeys(['a','b','c', 'a', 'x','b','x','a'])

dct
{'a': None, 'b': None, 'c': None, 'x': None}

list(dct)
Out: ['a', 'b', 'c', 'x']

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