Python数据类型详解（四）字典：dict
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
classdict(object):
"""
dict()->newemptydictionary
dict(mapping)->newdictionaryinitializedfromamappingobject's
(key,value)pairs
dict(iterable)->newdictionaryinitializedasifvia:
d={}
fork,viniterable:
d[k]=v
dict(**kwargs)->newdictionaryinitializedwiththename=valuepairs
inthekeywordargumentlist.Forexample:dict(one=1,two=2)
"""
defclear(self):#realsignatureunknown;restoredfrom__doc__
"""D.clear()->None.RemoveallitemsfromD."""
pass
defcopy(self):#realsignatureunknown;restoredfrom__doc__
"""D.copy()->ashallowcopyofD"""
pass
@staticmethod#knowncase
deffromkeys(*args,**kwargs):#realsignatureunknown
"""Returnsanewdictwithkeysfromiterableandvaluesequaltovalue."""
pass
defget(self,k,d=None):#realsignatureunknown;restoredfrom__doc__
"""D.get(k[,d])->D[k]ifkinD,elsed.ddefaultstoNone."""
pass
defitems(self):#realsignatureunknown;restoredfrom__doc__
"""D.items()->aset-likeobjectprovidingaviewonD'sitems"""
pass
defkeys(self):#realsignatureunknown;restoredfrom__doc__
"""D.keys()->aset-likeobjectprovidingaviewonD'skeys"""
pass
defpop(self,k,d=None):#realsignatureunknown;restoredfrom__doc__
"""
D.pop(k[,d])->v,removespecifiedkeyandreturnthecorrespondingvalue.
Ifkeyisnotfound,disreturnedifgiven,otherwiseKeyErrorisraised
"""
pass
defpopitem(self):#realsignatureunknown;restoredfrom__doc__
"""
D.popitem()->(k,v),removeandreturnsome(key,value)pairasa
2-tuple;butraiseKeyErrorifDisempty.
"""
pass
defsetdefault(self,k,d=None):#realsignatureunknown;restoredfrom__doc__
"""D.setdefault(k[,d])->D.get(k,d),alsosetD[k]=difknotinD"""
pass
defupdate(self,E=None,**F):#knownspecialcaseofdict.update
"""
D.update([E,]**F)->None.UpdateDfromdict/iterableEandF.
IfEispresentandhasa.keys()method,thendoes:forkinE:D[k]=E[k]
IfEispresentandlacksa.keys()method,thendoes:fork,vinE:D[k]=v
Ineithercase,thisisfollowedby:forkinF:D[k]=F[k]
"""
pass
defvalues(self):#realsignatureunknown;restoredfrom__doc__
"""D.values()->anobjectprovidingaviewonD'svalues"""
pass
def__contains__(self,*args,**kwargs):#realsignatureunknown
"""TrueifDhasakeyk,elseFalse."""
pass
def__delitem__(self,*args,**kwargs):#realsignatureunknown
"""Deleteself[key]."""
pass
def__eq__(self,*args,**kwargs):#realsignatureunknown
"""Returnself==value."""
pass
def__getattribute__(self,*args,**kwargs):#realsignatureunknown
"""Returngetattr(self,name)."""
pass
def__getitem__(self,y):#realsignatureunknown;restoredfrom__doc__
"""x.__getitem__(y)<==>x[y]"""
pass
def__ge__(self,*args,**kwargs):#realsignatureunknown
"""Returnself>=value."""
pass
def__gt__(self,*args,**kwargs):#realsignatureunknown
"""Returnself>value."""
pass
def__init__(self,seq=None,**kwargs):#knownspecialcaseofdict.__init__
"""
dict()->newemptydictionary
dict(mapping)->newdictionaryinitializedfromamappingobject's
(key,value)pairs
dict(iterable)->newdictionaryinitializedasifvia:
d={}
fork,viniterable:
d[k]=v
dict(**kwargs)->newdictionaryinitializedwiththename=valuepairs
inthekeywordargumentlist.Forexample:dict(one=1,two=2)
#(copiedfromclassdoc)
"""
pass
def__iter__(self,*args,**kwargs):#realsignatureunknown
"""Implementiter(self)."""
pass
def__len__(self,*args,**kwargs):#realsignatureunknown
"""Returnlen(self)."""
pass
def__le__(self,*args,**kwargs):#realsignatureunknown
"""Returnself<=value."""
pass
def__lt__(self,*args,**kwargs):#realsignatureunknown
"""Returnself<value."""
pass
@staticmethod#knowncaseof__new__
def__new__(*args,**kwargs):#realsignatureunknown
"""Createandreturnanewobject.Seehelp(type)foraccuratesignature."""
pass
def__ne__(self,*args,**kwargs):#realsignatureunknown
"""Returnself!=value."""
pass
def__repr__(self,*args,**kwargs):#realsignatureunknown
"""Returnrepr(self)."""
pass
def__setitem__(self,*args,**kwargs):#realsignatureunknown
"""Setself[key]tovalue."""
pass
def__sizeof__(self):#realsignatureunknown;restoredfrom__doc__
"""D.__sizeof__()->sizeofDinmemory,inbytes"""
pass
__hash__=None
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"
}
foriinuser_info:
print(i)
#循环输出所有的键入值
fork,vinuser_info.items():
print(k)
print(v)
以上就是本文的全部内容了，希望对大家熟练掌握Python数据结构能够有所帮助。