Python中集合的内建函数和内建方法学习教程

>>> s = set('cheeseshop')
>>> t = set('bookshop')
>>> s
set(['c', 'e', 'h', 'o', 'p', 's'])
>>> t
set(['b', 'h', 'k', 'o', 'p', 's'])
>>> s.issubset(t)
False
>>> s.issuperset(t)
False
>>> s.union(t)
set(['c', 'b', 'e', 'h', 'k', 'o', 'p', 's'])
>>> s.intersection(t)
set(['h', 's', 'o', 'p'])
>>> s.difference(t)
set(['c', 'e'])
>>> s.symmetric_difference(t)
set(['b', 'e', 'k', 'c'])
>>> s.copy()
set(['p', 'c', 'e', 'h', 's', 'o'])

>>> s.update(t)
>>> s
set(['c', 'b', 'e', 'h', 'k', 'o', 'p', 's'])

>>> s = set('cheeseshop')
>>> t = set('bookshop')
>>> s.intersection_update(t)
>>> s
set(['h', 's', 'o', 'p'])

>>> s = set('cheeseshop')
>>> t = set('bookshop')
>>> s.difference_update(t)
>>> s
set(['c', 'e'])

>>> s = set('cheeseshop')
>>> t = set('bookshop')
>>> s.symmetric_difference_update(t)
>>> s
set(['c', 'b', 'e', 'k'])

>>> s.add('o')
>>> s
set(['c', 'b', 'e', 'k', 'o'])

<p>>>> s.remove('b')
>>> s
set(['c', 'e', 'k', 'o'])
>>> s.remove('a')</p><p>Traceback (most recent call last):
 File "<pyshell#53>", line 1, in <module>
  s.remove('a')
KeyError: 'a'
</p>

>>> s.discard('a')
>>> s
set(['c', 'e', 'k', 'o'])
>>> s.discard('e')
>>> s
set(['c', 'k', 'o'])

>>> s.pop()
'c'
>>> s
set(['k', 'o'])

>>> s.clear()
>>> s
set([])