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。