Python中常见工厂函数用法详解

>>> type(6)

<type 'int'>

>>> type('python')

<type 'str'>

>>> type(u'love')

<type 'unicode'>

>>> class A():

...   pass

...

>>> a=A()

>>> type(a)

<type 'instance'>

>>> type(A)

<type 'classobj'>

>>> dict()

{}

>>> dict(one=1,two=2)

{'two': 2, 'one': 1}

>>> dict(zip(('one','two'),(1,2)))

{'two': 2, 'one': 1}

>>> dict([('one',1),('two',2)])

{'two': 2, 'one': 1}

>>> dict([['one',1],['two',2]])

{'two': 2, 'one': 1}

>>> dict((('one',1),('two',2)))

{'two': 2, 'one': 1}

>>> dict((['one',1],['two',2]))

{'two': 2, 'one': 1}

>>> s=set('python')

>>> s

set(['h', 'o', 'n', 'p', 't', 'y'])

>>> s.add(825)#可变集合

>>> s

set(['h', 'o', 'n', 'p', 't', 'y', 825])

>>> s=frozenset('python')

>>> s

frozenset(['h', 'o', 'n', 'p', 't', 'y'])

>>> s.add()#不可变集合

AttributeError: 'frozenset' object has no attribute 'add'