python3字典方法

>>> type({})
<class 'dict'>
>>> a={}
>>> a
{}
>>> a[5]=6
>>> a
{5: 6}
>>>

>>> dir(dict)

['__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'items', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values']
>>>


'clear'清除, 'copy'复制, 'fromkeys'迭代：值, 'get'获取, 'items'键值对, 'keys'键, 'pop'弹出, 'popitem'随机弹出, 'setdefault'设置默认, 'update'更新, 'values'值


clear(self): 
>>> d={'a':1,"b":2}
>>> d.clear()
>>> d
{}

copy(self): 
>>> {'a':1,"b":2}.copy()
{'a': 1, 'b': 2}
>>>

fromkeys(*args, **kwargs): 
>>> d={}
>>> nd=d.fromkeys([1,2,3,4],[5,6,7,8])
>>> d
{}
>>> nd
{1: [5, 6, 7, 8], 2: [5, 6, 7, 8], 3: [5, 6, 7, 8], 4: [5, 6, 7, 8]}
>>>

get(self, k, d=None): 
>>> {1:2,2:4,3:6}.get(4,7)
7
>>>

items(self): 
>>> {1:2,2:4,3:6}.keys()
dict_keys([1, 2, 3])
>>> {1:2,2:4,3:6}.values()
dict_values([2, 4, 6])
>>> {1:2,2:4,3:6}.items()
dict_items([(1, 2), (2, 4), (3, 6)])
>>>
可迭代

keys(self): 
>>> {1:2,2:4,3:6}.keys()
dict_keys([1, 2, 3])
>>> {1:2,2:4,3:6}.values()
dict_values([2, 4, 6])
>>> {1:2,2:4,3:6}.items()
dict_items([(1, 2), (2, 4), (3, 6)])
>>>
可迭代

pop(self, k, d=None): 
>>> d={1:2,2:4,3:6}
>>> d.pop(2)
4
>>> d
{1: 2, 3: 6}
>>>

popitem(self): 
>>> d={1:2,2:4,3:6}
>>> d.popitem()
(3, 6)
>>> d
{1: 2, 2: 4}
>>>

setdefault(self, k, d=None): 
>>> d={1:2,2:4,3:6}
>>> d.setdefault(7)
>>> d
{1: 2, 2: 4, 3: 6, 7: None}
>>>

update(self, E=None, **F): 
>>> d={1:2,2:4,3:6}
>>> d.update({1:3,5:10})
>>> d
{1: 3, 2: 4, 3: 6, 5: 10}
>>>

values(self): 
>>> {1:2,2:4,3:6}.keys()
dict_keys([1, 2, 3])
>>> {1:2,2:4,3:6}.values()
dict_values([2, 4, 6])
>>> {1:2,2:4,3:6}.items()
dict_items([(1, 2), (2, 4), (3, 6)])
>>>
可迭代