Python手册学习（二）：集合

1.集合的相关操作

>>> x=set('abcde')
>>> y=set('bdxyz')
>>> x
{'d', 'b', 'e', 'a', 'c'}
>>> y
{'d', 'x', 'b', 'y', 'z'}
>>> 'e'in x
True
>>> z=x.intersection(y)
>>> z
{'d', 'b'}
>>> z.add('SPAM')
>>> z
{'d', 'b', 'SPAM'}
>>> z.update(set(['x','y']))
>>> z
{'d', 'x', 'b', 'SPAM', 'y'}
>>> z.remove('b')
>>> z
{'d', 'x', 'SPAM', 'y'}
>>> S=set([1,2,3])
>>> S
{1, 2, 3}
>>> S.union([3,4])
{1, 2, 3, 4}
>>> S.intersection((1,3,5))
{1, 3}
>>> S.issubset(range(-5,5))
True

2、集合的解析形式

>>> {x**2 for x in [1,2,3,4]}
{16, 1, 9, 4}
>>> {x for x in 'spam'}
{'m', 's', 'p', 'a'}
>>> {c*4 for c in 'spamham'}
{'aaaa', 'hhhh', 'pppp', 'ssss', 'mmmm'}

3、布尔值

>>> True == 1
True
>>> True is 1
False
>>> True + 4
5