Python数据类型之字典

一.基本数据类型
　　整数：int
　　字符串：str(注：\t等于一个tab键)
　　布尔值： bool
　　列表：list
　　列表用[]
　　元祖：tuple
　　元祖用（）
　　字典：dict

注：所有的数据类型都存在想对应的类列里，元祖和列表功能一样，列表可以修改，元祖不能修改。

二.字典所有数据类型：

常用操作：

索引

新增

删除

键、值、键值对

循环

长度

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)
"""
def clear(self): # real signature unknown; restored from __doc__
""" D.clear() -> None.  Remove all items from D. """
pass

def copy(self): # real signature unknown; restored from __doc__
""" D.copy() -> a shallow copy of D """
pass

@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

def items(self): # real signature unknown; restored from __doc__
""" D.items() -> a set-like object providing a view on D's items """
pass

def keys(self): # real signature unknown; restored from __doc__
""" D.keys() -> a set-like object providing a view on D's keys """
pass

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

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

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

def values(self): # real signature unknown; restored from __doc__
""" D.values() -> an object providing a view on D's values """
pass

def __contains__(self, *args, **kwargs): # real signature unknown
""" True if D has a key k, else False. """
pass

def __delitem__(self, *args, **kwargs): # real signature unknown
""" Delete self[key]. """
pass

def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
pass

def __getattribute__(self, *args, **kwargs): # real signature unknown
""" Return getattr(self, name). """
pass

def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass

def __ge__(self, *args, **kwargs): # real signature unknown
""" Return self>=value. """
pass

def __gt__(self, *args, **kwargs): # real signature unknown
""" Return self>value. """
pass

def __init__(self, seq=None, **kwargs): # known special case of dict.__init__
"""
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)
# (copied from class doc)
"""
pass

def __iter__(self, *args, **kwargs): # real signature unknown
""" Implement iter(self). """
pass

def __len__(self, *args, **kwargs): # real signature unknown
""" Return len(self). """
pass

def __le__(self, *args, **kwargs): # real signature unknown
""" Return self<=value. """
pass

def __lt__(self, *args, **kwargs): # real signature unknown
""" Return self<value. """
pass

@staticmethod # known case of __new__
def __new__(*args, **kwargs): # real signature unknown
""" Create and return a new object.  See help(type) for accurate signature. """
pass

def __ne__(self, *args, **kwargs): # real signature unknown
""" Return self!=value. """
pass

def __repr__(self, *args, **kwargs): # real signature unknown
""" Return repr(self). """
pass

def __setitem__(self, *args, **kwargs): # real signature unknown
""" Set self[key] to value. """
pass

def __sizeof__(self): # real signature unknown; restored from __doc__
""" D.__sizeof__() -> size of D in memory, in bytes """
pass

__hash__ = None

dict
三.所有字典数据类型举例

user_info = {
0 :"zhangyanlin",
"age"  :"18",
2  :"pythoner"
}
#获取所有的key
print(user_info.keys())

#获取所有的values
print(user_info.values())

#获取所有的key和values
print(user_info.items())

clear清除所有的内容
user_info.clear()
print(user_info)

#get 根据key获取值，如果key不存在，可以指定一个默认值
val = user_info.get('age')
print(val)

#update批量更新
test = {
'a':111,
'b':222
}
user_info.update(test)
print(user_info)

四.索引

#如果没有key，会报错
user_info = {
"name" :'zhangyanlin',
"age"  :18,
"job"  :'pythoner'
}
print(user_info['name'])

五.for循环

#循环
user_info = {
0 :"zhangyanlin",
"age"  :"18",
2  :"pythoner"
}
for i in user_info:
print(i)

#循环输出所有的键入值
for k,v in user_info.items():
print(k)
print(v)