Comparing two sets in python

问题

Hi guys,i have a doubt regarding comparing two sets

    >>> x = {"a","b","1","2","3"}  
    >>> y = {"c","d","f","2","3","4"}  
    >>> z=x<y        
    >>> print(z)
    False
    >>> z=x>y
    >>> print(z)
    False

In the above logic,for both z=x<y and z=x>y. I'm getting output as False,whereas one of the expression should return True. Could anyone explain me why?

回答1:

The < and > operators are testing for strict subsets. Neither of those sets is a subset of the other.

{1, 2} < {1, 2, 3}  # True
{1, 2} < {1, 3}  # False
{1, 2} < {1, 2}  # False -- not a *strict* subset
{1, 2} <= {1, 2}  # True -- is a subset

回答2:

Straight from the python documentation --

In addition, both Set and ImmutableSet support set to set comparisons. Two sets are equal if and only if every element of each set is contained in the other (each is a subset of the other). A set is less than another set if and only if the first set is a proper subset of the second set (is a subset, but is not equal). A set is greater than another set if and only if the first set is a proper superset of the second set (is a superset, but is not equal).

回答3:

When working with sets, > and < are relational operators. hence, these operations are used to see if one set is the proper subset of the other, which is False for as neither is the proper subset of the other.

来源：https://stackoverflow.com/questions/49677114/comparing-two-sets-in-python