保持冻结集中元素的顺序

与其直接在

set

frozenset

unique_everseen

from itertools import filterfalsedef unique_everseen(iterable, key=None):    "List unique elements, preserving order. Remember all elements ever seen."    # unique_everseen('AAAABBBCCDAABBB') --> A B C D    # unique_everseen('ABBCcAD', str.lower) --> A B C D    seen = set()    seen_add = seen.add    if key is None:        for element in filterfalse(seen.__contains__, iterable): seen_add(element) yield element    else:        for element in iterable: k = key(element) if k not in seen:     seen_add(k)     yield element

基本上，这将解决您使用时的问题

key=frozenset

>>> x = [('a',1,2), ('b',3,4), ('x',5,6), ('a',2,1)]>>> list(unique_everseen(x, key=frozenset))[('a', 1, 2), ('b', 3, 4), ('x', 5, 6)]

这 将按原样 返回元素 ， 并且还保持元素之间的相对顺序。