python 字典dict方法
dict方法
字典(dict)：
特性：
1.由键值对组成的序列。
2.字典是无序的（非线性序列）。 字典的定义（初始化）：
d = dict()
d1 = {'k1':'v1','k2','v2'} 生成字典方法： d1 = {'k1':v1,'k2':'v2'}
字典方法：
class dict(object):
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
#字典初始化，可接收name=value形式的参数，生成字典
------------------------------------------------------------------------------
example:
>>> d1 = dict(k1 = 'v1', age = 27, name = 'handsome man')
>>> print(d1)
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
------------------------------------------------------------------------------
"""
def clear(self): # real signature unknown; restored from __doc__
""" D.clear() -> None. Remove all items from D. """
pass
#删除列表中的所有元素。
-------------------------------------------------------------------------------
example:
>>> print(d1)
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d1.clear()
>>> print(d1)
{}
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
def copy(self): # real signature unknown; restored from __doc__
""" D.copy() -> a shallow copy of D """
pass
#复制，浅复制，只复制字段第一层的元素。
-------------------------------------------------------------------------------
>>> d1 = dict(k1 = 'v1', age = 27, name = 'handsome man')
>>> d2 = d1.copy()
>>> print(d2)
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d3 = {'k1':[1,2,3,4,5,6]}
>>> d4 = d3.copy()
>>> d3['k1'].insert(0,100)
>>> print(d3,d4)
{'k1': [100, 1, 2, 3, 4, 5, 6]} {'k1': [100, 1, 2, 3, 4, 5, 6]}
>>>
-------------------------------------------------------------------------------
@staticmethod # known case
def fromkeys(*args, **kwargs): # real signature unknown
""" Returns a new dict with keys from iterable and values equal to value. """
pass
#
def get(self, k, d=None): # real signature unknown; restored from __doc__
""" D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """
pass
#获取键k对应的value，如果k在字典中返回value，否则返回d,d默认值为none
-------------------------------------------------------------------------------
>>> d1
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d1.get('k1')
'v1'
>>> d1.get('k2')
>>> print(d1.get('k2'))
None
>>> d1.get('k2','nothiskey')
'nothiskey'
-------------------------------------------------------------------------------
def items(self): # real signature unknown; restored from __doc__
""" D.items() -> a set-like object providing a view on D's items """
#返回一个键值对组成的，dict_items对象（可迭代）
pass
------------------------------------------------------------------------------
>>> d1.items()
dict_items([('k1', 'v1'), ('age', 27), ('name', 'handsome man')])
>>> type(d1.items())
<class 'dict_items'>
>>> for i,j in d1.items():
... print(i,j)
...
k1 v1
age 27
name handsome man
>>>
------------------------------------------------------------------------------
def keys(self): # real signature unknown; restored from __doc__
""" D.keys() -> a set-like object providing a view on D's keys """
pass
#返回一个key组成的,dict_keys对象（可迭代）
------------------------------------------------------------------------------
>>> d1.keys()
dict_keys(['k1', 'age', 'name'])
>>> type(d1.keys())
<class 'dict_keys'>
>>> for i in d1.keys():
... print(i)
...
k1
age
name
------------------------------------------------------------------------------
def pop(self, k, d=None): # real signature unknown; restored from __doc__
"""
D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
If key is not found, d is returned if given, otherwise KeyError is raised
"""
pass
#移除一个键值对，并反馈该键所对应的值。
------------------------------------------------------------------------------
>>> d1
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d1.pop('k1')
'v1'
------------------------------------------------------------------------------
def popitem(self): # real signature unknown; restored from __doc__
"""
D.popitem() -> (k, v), remove and return some (key, value) pair as a
2-tuple; but raise KeyError if D is empty.
"""
pass
#随机移除一个键值对，并返回该键值对组成的元组
------------------------------------------------------------------------------
>>> d1
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d1.popitem()
('name', 'handsome man')
>>> d1
{'k1': 'v1', 'age': 27}
>>>
------------------------------------------------------------------------------
def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
""" D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """
pass
def update(self, E=None, **F): # known special case of dict.update
"""
D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
If E is present and has a .keys() method, then does: for k in E: D[k] = E[k]
If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v
In either case, this is followed by: for k in F: D[k] = F[k]
"""
pass
#用一个字典来更新自己。
------------------------------------------------------------------------------
>>> d2 = {'name':'handsome man','k2':'v2'}
>>> d1 = dict(k1 = 'v1', age = 27, name = 'handsome man')
>>> d2.update(d1)
>>> d2
{'name': 'handsome man', 'k2': 'v2', 'k1': 'v1', 'age': 27}
------------------------------------------------------------------------------
def values(self): # real signature unknown; restored from __doc__
""" D.values() -> an object providing a view on D's values """
pass
#返回value组成的dict_values对象（可迭代）
-------------------------------------------------------------------------------
>>> d1
{'k1': 'v1', 'age': 27, 'name': 'handsome man'}
>>> d1.values()
dict_values(['v1', 27, 'handsome man'])
>>> for i in d1.values():
... print(i)
...
v1
27
handsome man
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