Python:Frozensets比较 [英] Python: frozensets comparison

问题描述

考虑以下脚本:

# multipleSmallFrozensets is a list of 7 frozensets of differenet number of string objects
multipleSmallFrozensets = [
    frozenset({'YHR007C', 'YHR042W'}),
    frozenset({'YPL274W'}),
    frozenset({'YCL064C'}),
    frozenset({'YBR166C'}),
    frozenset({'YEL041W', 'YJR049C'}),
    frozenset({'YGL142C'}),
    frozenset({'YJL134W', 'YKR053C'})]

# singleFrozenset is a frozenset of 3410 string objects
singleFrozenset = frozenset({'YIL140W','YLR268W','YLR357W','YJL155C','YHR067W',
'YAL008W','YBR255W','YFR027W','YGR148C','YJR122W','YJL204C','YJL093C','YLR244C',
'YNL003C','YBR111W-A', ...})

# don't forget that i is of type frozenset [just saying!]
for i in multipleSmallFrozensets:
      if i <= singleFrozenset: print "First option entered"
      elif len(i) == 1: print "Second option entered"
      else: print "Third option entered"

神秘的输出是

First option entered
Second option entered
Second option entered
First option entered
Third option entered
First option entered
First option entered

这些if-else条件正在检查两种情况:a)i< = singleFrozenset，b)len(i)== 1.但是，我无法找出第一个条件，即与之匹配的案例是1、4、6和7.在这些案例中，我找不到这些冻结集之间的链接！ 知道为什么吗?

These if-else conditions are checking for two cases a) i <= singleFrozenset, and b) len(i) == 1. The second condition is simple; however, I couldn't figure out the first condition where the cases that matched with are 1, 4, 6, and 7. I couldn't find a link between these frozen sets in these cases! Any idea why?

推荐答案

设置运算符<=等效于.issubset()方法. A <= B为真，且仅当A的每个元素也属于B时.

Set operator <= is equivalent to the .issubset() method. A <= B is true if and only if each element of A also belongs to B.

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