python函数中文手册

1、内置函数一，文档说明原始文档来自于pythonv2.7.2中文译文和用法尚不完全，您可以自由修改和完善，您可以在文档结尾鸣谢添上您的名字，我们将会感谢您做的贡献！二，函数列表1,取绝对值abs(x)Returntheabsolutevalueofanumber.Theargumentmaybeaplainorlongintegerorafloatingpointnumber.Iftheargumentisacomplexnumber,itsmagnitudeisreturned.如果你不知道绝对值什么意思，那就要补一下小学数学了！基本用法2,all(iterable)ReturnTrueifa

2、llelementsoftheiterablearetrue(oriftheiterableisempty).Equivalentto:3 .any(iterable)ReturnTrueifanyelementoftheiterableistrue.Iftheiterableisempty,returnFalse.Equivalentto:4 .basestring()Thisabstracttypeisthesuperclassforstrandunicode.Itcannotbecalledorinstantiated,butitcanbeusedtotestwhetheranobjec

3、tisaninstanceofstrorunicode.isinstance(obj,basestring)isequivalenttoisinstance(obj,(str,unicode).是字符串和字符编码的超类，是抽象类型。不能被调用或者实例化。可以用来判断实例是否为字符申或者字符编码。方法:5 .二进制转换bin(x)Convertanintegernumbertoabinarystring.TheresultisavalidPythonexpression.IfxisnotaPythonin£object,ithastodefineanindex()methodthatr

4、eturnsaninteger.转换成二进制表达方法:6 .布尔类型bool(x)ConvertavaluetoaBoolean,usingthestandardtruthtestingprocedure.Ifxisfalseoromitted,thisreturnsFalse;otherwiseitreturnsTrue.boolisalsoaclass,whichisasubclassofint.Classboolcannotbesubclassedfurther.ItsonlyinstancesareFalseandTrue布尔类型的转化用法:7 .二进制数组的转化bytearray(s

5、ource,encoding,errors)Returnanewarrayofbytes.Thebytearraytypeisamutablesequenceofintegersintherange0<=x<256.Ithasmostoftheusualmethodsofmutablesequences,describedinMutableSequenceTypes,aswellasmostmethodsthatthestrtypehas,seeStringMethodsTheoptionalsourceparametercanbeusedtoinitializethearrayi

6、nafewdifferentways:?Ifitisastring,youmustalsogivetheencoding(andoptionally,errors)parameters;bytearray()thenconvertsthestringtobytesusingstr.encode().?Ifitisaninteger,thearraywillhavethatsizeandwillbeinitializedwithnullbytes.?Ifitisanobjectconformingtothebufferinterface,aread-onlybufferoftheobjectwi

7、llbeusedtoinitializethebytesarray.?Ifitisaniterable,itmustbeaniterableofintegersintherange0<=x<256,whichareusedastheinitialcontentsofthearray.Withoutanargument,anarrayofsize0iscreated.8.callable(object)ReturnTrueiftheobjectargumentappearscallable,Falseifnot.Ifthisreturnstrue,itisstillpossiblet

8、hatacallfails,butifitisfalse,callingobjectwillneversucceed.Notethatclassesarecallable(callingaclassreturnsanewinstance);classinstancesarecallableiftheyhavea_call_()method.9.数字转化成字符chr(i)ReturnastringofonecharacterwhoseASCIIcodeistheintegeri.Forexample,chr(97)returnsthestring'a'.Thisistheinve

9、rseoford().Theargumentmustbeintherange0.255,inclusive;ValueErrorwillberaisedifiisoutsidethatrange.Seealsounichr().用法：10.classmethod(function)Aclassmethodreceivestheclassasimplicitfirstargument,justlikeaninstancemethodreceivestheinstance.Todeclareaclassmethod,usethisidiom:11 .两两比较cmp(x,y)Comparethetw

10、oobjectsxandyandreturnanintegeraccordingtotheoutcome.Thereturnvalueisnegativeifx<y,zeroifx=yandstrictlypositiveifx>y.X小于X输出负(-1),X等于Y输出零(0),X大于Y输出正(1)用法：12 .compile(source,filename,mode,flags,dont_inherit)CompilethesourceintoacodeorASTobject.Codeobjectscanbeexecutedbyanexecstatementorevaluated

11、byacalltoeval().sourcecaneitherbeastringoranASTobject.RefertotheastmoduledocumentationforinformationonhowtoworkwithASTplex(real,imag)Create a complex number with the valuereal+imag*jorconvertastringornumbertoacomplexnumber.Ifthefirstparameterisastring,itwillbeinterpretedasacomplexnumbe

12、randthefunctionmustbecalledwithoutasecondparameter.Thesecondparametercanneverbeastring.Eachargumentmaybeanynumerictype(includingcomplex).Ifimagisomitted,itdefaultstozeroandthefunctionservesasanumericconversionfunctionlikeint(),long()andfloat().Ifbothargumentsareomitted,returns0j.14 .delattr(object,n

13、ame)Thisisarelativeofsetattr().Theargumentsareanobjectandastring.Thestringmustbethenameofoneoftheobject'sattributes.Thefunctiondeletesthenamedattribute,providedtheobjectallowsit.Forexample,delattr(x,'foobar')isequivalenttodelx.foobar.15 .字典dict(arg)Createanewdatadictionary,optionallywith

14、itemstakenfromarg.ThedictionarytypeisdescribedinMappingTypesdict.Forothercontainersseethebuiltinlist,set,andtupleclasses,andthecollectionsmodule.16 .很重要的函数，属性输出dir(object)Withoutarguments,returnthelistofnamesinthecurrentlocalscope.Withanargument,attempttoreturnalistofvalidattributesforthatobject.方法1

15、7 .divmod(a,b)Taketwo(noncomplex)numbersasargumentsandreturnapairofnumbersconsistingoftheirquotientandremainderwhenusinglongdivision.Withmixedoperandtypes,therulesforbinaryarithmeticoperatorsapply.Forplainandlongintegers,theresultisthesameas(a/b,a%b).Forfloatingpointnumberstheresultis(q,a%b),whereqi

16、susuallymath.floor(a/b)butmaybe1lessthanthat.Inanycaseq*b+a%bisveryclosetoa,ifa%bisnon-zeroithasthesamesignasb,and0<=abs(a%b)<abs(b).18.enumerate(sequence,start=0)Returnanenumerateobject.sequencemustbeasequence,aniterator,orsomeotherobjectwhichsupportsiteration.Thenext()methodoftheiteratorretu

17、rnedbyenumerate()returns a tuple containing a count (fromstartwhichdefaultsto0)andthecorrespondingvalueobtainedfromiteratingoveriterable.enumerate。isusefulforobtaininganindexedseries:(0,seq0),(1,seq1),(2,seq2)19.eval(expression,globals,locals)Theargumentsareastringandoptionalglobalsandlocals.Ifprovi

18、ded,globalsmustbeadictionary.Ifprovided,localscanbeanymappingobject.Changedinversion2.4:formerlylocalswasrequiredtobeadictionary.20.execfile(filename,globals,locals)Thisfunctionissimilartotheexecstatement,butparsesafileinsteadofastring.Itisdifferentfromtheimportstatementinthatitdoesnotusethemodulead

19、ministrationitreadsthefileunconditionallyanddoesnotcreateanewmodule.和exec很相似的函数21.file(filename,mode,bufsize)Constructorfunctionforthefiletype,describedfurtherinsectionFileObjects.Theconstructor'sargumentsarethesameasthoseoftheopen()built-infunctiondescribedbelow.Whenopeningafile,it'sprefera

20、bletoouse)insteadofinvokingthisconstructordirectly.fileismoresuitedtotypetesting(forexample,writingisinstance(f,file).filter(function,iterable)Constructalistfromthoseelementsofiterableforwhichfunctionreturnstrue.iterablemaybeeitherasequence,acontainerwhichsupportsiteration,oraniterator.Ifiterableisa

21、stringoratuple,theresultalsohasthattype;otherwiseitisalwaysalist.IffunctionisNone,theidentityfunctionisassumed,thatis,allelementsofiterablethatarefalseareremoved.Notethatfilter(function,iterable)isequivalenttoitemforiteminiterableiffunction(item)iffunctionisnotNoneanditemforiteminiterableifitemiffun

22、ctionisNone.Seeitertools.ifilter()anditertools.ifilterfalse()foriteratorversionsofthisfunction,includingavariationthatfiltersforelementswherethefunctionreturnsfalse.23.浮点数值转化float(x)用法：format(value,format_spec)Convertavaluetoa“formatted“reeepntation,ascontrolledbyformat_spec.Theinterpretationofforma

23、t_specwilldependonthetypeofthevalueargument,howeverthereisastandardformattingsyntaxthatisusedbymostbuilt-intypes:FormatSpecificationMini-Language.25 frozenset(iterable)Returnafrozensetobject,optionallywithelementstakenfromiterable.ThefrozensettypeisdescribedinSetTypesset,frozenset.For other containe

24、rs see the built indict,list,andtupleclasses,andthecollectionsmodule.26 .getattr(object,name,default)Rmustbeastring.Ifthestringisthenameofoneoftheobject'sattributes,theresultisthevalueofthatattribute.Forexample,getattr(x,'foobar')isequivalentt

25、ox.foobar.Ifthenamedattributedoesnotexist,defaultisreturnedifprovided,otherwiseAttributeErrorisraised.27 .全局参数globals()Returnadictionaryrepresentingthecurrentglobalsymboltable.Thisisalwaysthedictionaryofthecurrentmodule(insideafunctionormethod,thisisthemodulewhereitisdefined,notthemodulefromwhichiti

26、scalled).hasattr(object,name)Returnthehashvalueoftheobject(ifithasone).Hashvaluesareintegers.Theyareusedtoquicklycomparedictionarykeysduringadictionarylookup.Numericvaluesthatcompareequalhavethesamehashvalue(eveniftheyareofdifferenttypes,asisthecasefor1and1.0).29.hash(object)Returnthehashvalueoftheo

27、bject(ifithasone).Hashvaluesareintegers.Theyareusedtoquicklycomparedictionarykeysduringadictionarylookup.Numericvaluesthatcompareequalhavethesamehashvalue(eveniftheyareofdifferenttypes,asisthecasefor1and1.0).30. 很重要的帮助函数方法help(object)31. 十六进制转化hex(x)Convertanintegernumber(ofanysize)toahexadecimalstr

28、ing.TheresultisavalidPythonexpression.用法：32. 内存地址id(object)Returnthe“identity“ofanobject.Thisisaninteger(orlonginteger)whichisguaranteedtobeuniqueandconstantforthisobjectduringitslifetime.Twoobjectswithnon-overlappinglifetimesmayhavethesameid()value.如果想知道某个对象的内存地址，用这个内置函数，返回的是10进制的地址。33.input(prompt

29、)Equivalenttoeval(raw_input(prompt).34.int(x,base)Convertastringornumbertoaplaininteger.Iftheargumentisastring,itmustcontainapossiblysigneddecimalnumberrepresentableasaPythoninteger,possiblyembeddedinwhitespace.Thebaseparametergivesthebasefortheconversion(whichis10bydefault)andmaybeanyintegerinthera

30、nge2,36,orzero.Ifbaseiszero,theproperradixisdeterminedbasedonthecontentsofstring;theinterpretationisthesameasforintegerliterals.(SeeNumericliterals.)Ifbaseisspecifiedandxisnotastring,TypeErrorisraised.Otherwise,theargumentmaybeaplainorlongintegerorafloatingpointnumber.Conversionoffloatingpointnumber

31、stointegerstruncates(towardszero).Iftheargumentisoutsidetheintegerrangealongobjectwillbereturnedinstead.Ifnoargumentsaregiven,returns0.35.isinstance(object,classinfo)Returntrueiftheobjectargumentisaninstanceoftheclassinfoargument,orofa(directorindirect)subclassthereof.Alsoreturntrueifclassinfoisatyp

32、eobject(new-styleclass)andobjectisanobjectofthattypeorofa(directorindirect)subclassthereof.Ifobjectisnotaclassinstanceoranobjectofthegiventype,thefunctionalwaysreturnsfalse.Ifclassinfoisneitheraclassobjectnoratypeobject,itmaybeatupleofclassortypeobjects,ormayrecursivelycontainothersuchtuples(otherse

33、quencetypesarenotaccepted).Ifclassinfoisnotaclass,type,ortupleofclasses,types,andsuchtuples,aTypeErrorexceptionisraised.36.issubclass(class,classinfo)Returntrueifclassisasubclass(directorindirect)ofclassinfo.Aclassisconsideredasubclassofitself.classinfomaybeatupleofclassobjects,inwhichcaseeveryentry

34、inclassinfowillbechecked.Inanyothercase,aTypeErrorexceptionisraised.37. 导管，窗口，容器，数据的窗口化iter(o,sentinel)Returnaniteratorobject.Thefirstargumentisinterpretedverydifferentlydependingonthepresenceofthesecondargument.Withoutasecondargument,omustbeacollectionobjectwhichsupportstheiterationprotocol(theiter

35、()method),oritmustsupportthesequenceprotocol(thegetitem()methodwithintegerargumentsstartingat0).Ifitdoesnotsupporteitherofthoseprotocols,TypeErrorisraised.Ifthesecondargument,sentinel,isgiven,thenomustbeacallableobject.Theiteratorcreatedinthiscasewillcallowithnoargumentsforeachcalltoitsnext()method;

36、ifthevaluereturnedisequaltosentinel,StopIterationwillberaised,otherwisethevaluewillbereturned.iter(o,sentinel)返回一个迭代器对象。第一个参数根据第二个参数进行编译。第二参数为空，。必须是支持迭代器的协议(the_iter_()method)的集合对象，或者支持顺序协议(the_getitem_()methodwithintegerargumentsstaringat0).如果不支持其中任意一种协议，程序将会抛出类型异常。假如第二个参数被给出，然后O必须是一个可被调用的对象。迭代器被创建

37、万一will掉用Owith没有参数foreachcalltoitsnext()method;如果返回值和初始值相同l,StopIteration将会抛出,否则值会被返回！38. 计算长度(常用函数)len(s)Returnthelength(thenumberofitems)ofanobject.Theargumentmaybeasequence(string,tupleorlist)oramapping(dictionary).用法：39. 转化成列表list(iterable)Returnalistwhoseitemsarethesameandinthesameorderasiterabl

38、e'sitems.iterablemaybeeitherasequence,acontainerthatsupportsiteration,oraniteratorobject.Ifiterableisalreadyalist,acopyismadeandreturned,similartoiterable:.Forinstance,list('abc')returns'a','b','c'andlist(1,2,3)returns1,2,3.Ifnoargumentisgiven,returnsanewemptylist

39、,.40.locals()Updateandreturnadictionaryrepresentingthecurrentlocalsymboltable.Freevariablesarereturnedbylocals()whenitiscalledinfunctionblocks,butnotinclassblocks.Updateandreturnadictionary更新和返回字典long(x,base)Convertastringornumbertoalonginteger.Iftheargumentisastring,itmustcontainapossiblysignednumb

40、erofarbitrarysize,possiblyembeddedinwhitespace.Thebaseargumentisinterpretedinthesamewayasforint(),andmayonlybegivenwhenxisastring.Otherwise,theargumentmaybeaplainorlongintegerorafloatingpointnumber,andalongintegerwiththesamevalueisreturned.Conversionoffloatingpointnumberstointegerstruncates(towardsz

41、ero).Ifnoargumentsaregiven,returns0L.42 .map(function,iterable,.)Applyfunctiontoeveryitemofiterableandreturnalistoftheresults.Ifadditionaliterableargumentsarepassed,functionmusttakethatmanyargumentsandisappliedtotheitemsfromalliterablesinparallel.Ifoneiterableisshorterthananotheritisassumedtobeexten

42、dedwithNoneitems.IffunctionisNone,theidentityfunctionisassumed;iftherearemultiplearguments,map()returnsalistconsistingoftuplescontainingthecorrespondingitemsfromalliterables(akindoftransposeoperation).Theiterableargumentsmaybeasequenceoranyiterableobject;theresultisalwaysalist.43 .最大值max(iterable,ar

43、gs.,key)Withasingleargumentiterable,returnthelargestitemofanon-emptyiterable(suchasastring,tupleorlist).Withmorethanoneargument,returnthelargestofthearguments.Theoptionalkeyargumentspecifiesaone-argumentorderingfunctionlikethatusedforlist.sort().Thekeyargument,ifsupplied,mustbeinkeywordform(forexamp

44、le,max(a,b,c,key=func).44 .memoryview(obj)Returna“memoryview"objectcreatedfromthegivenargument.Seememoryviewtypeformoreinformation.45 .最小值min(iterable,args儿key)Withasingleargumentiterable,returnthesmallestitemofanon-emptyiterable(suchasastring,tupleorlist).Withmorethanoneargument,returnthesmall

45、estofthearguments.46 .迭代以后的函数next(iterator,default)Retrievethenextitemfromtheiteratorbycallingitsnext()method.Ifdefaultisgiven,itisreturnediftheiteratorisexhausted,otherwiseStopIterationisraised.用法:object()Returnanewfeaturelessobject.objectisabaseforallnewstyleclasses.Ithasthemethodsthatarecommontoa

46、llinstancesofnewstyleclasses.48 .八进制字符串的转化oct(x)Convertanintegernumber(ofanysize)toanoctalstring.TheresultisavalidPythonexpression.用法:49 .open(filename,mode,bufsize)Openafile,returninganobjectofthefiletypedescribedinsectionFileObjects.Ifthefilecannotbeopened,IOErrorisraised.Whenopeningafile,it's

47、preferpenOouseinsteadofinvokingthefileconstructordirectly.50 .字符转化成ASCn码ord(c)Givenastringoflengthone,returnanintegerrepresentingtheUnicodecodepointofthecharacterwhentheargumentisaunicodeobject,orthevalueofthebytewhentheargumentisan8-bitstring.Forexample,ord('a')returnstheinteger97,ord(u'

48、;u2020')returns8224.Thisistheinverseofchr()for8-bitstringsandofunichr()forunicodeobjects.IfaunicodeargumentisgivenandPythonwasbuiltwithUCS2Unicode,thenthecharacter'scodepointmustbeintherange0.65535inclusive;otherwisethestringlengthistwo,andaTypeErrorwillberaised.pow(x,y,z)Returnxtothepowery;

49、ifzispresent,returnxtothepowery,moduloz(computedmoreefficientlythanpow(x,y)%z).Thetwo-argumentformpow(x,y)isequivalenttousingthepoweroperator:x*y.52. print函数原来本身就是函数。print(object,.,sep='',end='n',file=sys.stdout)Printobject(s)tothestreamfile,separatedbysepandfollowedbyend.sep,endandf

50、ile,ifpresent,perty(fget,fset,fdel,doc)Returnapropertyattributefornew-styleclasses(classesthatderivefromobject).54.range(start,stop,step)起始位置，终止位置，步长55.raw_input(prompt)Ifthepromptargumentispresent,itiswrittentostandardoutputwithoutatrailingnewline.用法：56.reduce(fu

51、nction,iterable,initializer)Applyfunctionoftwoargumentscumulativelytotheitemsofiterable,fromlefttoright,soastoreducetheiterabletoasinglevalue.Forexample,reduce(lambdax,y:x+y,1,2,3,4,5)calculates(1+2)+3)+4)+5).Theleftargument,x,istheaccumulatedvalueandtherightargument,y,istheupdatevaluefromtheiterabl

52、e.Iftheoptionalinitializerispresent,itisplacedbeforetheitemsoftheiterableinthecalculation,andservesasadefaultwhentheiterableisempty.Ifinitializerisnotgivenanditerablecontainsonlyoneitem,thefirstitemisreturned.57. 重载模块，很重要的函数reload(module)58.repr(object)Returnastringcontainingaprintablerepresentation

53、ofanobject.Thisisthesamevalueyieldedbyconversions(reversequotes).Itissometimesusefultobeabletoaccessthisoperationasanordinaryfunction.Formanytypes,thisfunctionmakesanattempttoreturnastringthatwouldyieldanobjectwiththesamevaluewhenpassedtoeval(),otherwisetherepresentationisastringenclosedinanglebrack

54、etsthatcontainsthenameofthetypeoftheobjecttogetherwithadditionalinformationoftenincludingthenameandaddressoftheobject.Aclasscancontrolwhatthisfunctionreturnsforitsinstancesbydefiningarepr()method.59 .reversed(seq)Returnareverseiterator.seqmustbeanobjectwhichhasareversed()methodorsupportsthesequencep

55、rotocol(thelen()methodandthegetitem()methodwithintegerargumentsstartingat0).60 .round(x,n)Returnthefloatingpointvaluexroundedtondigitsafterthedecimalpoint.Ifnisomitted,itdefaultstozero.Theresultisafloatingpointnumber.Valuesareroundedtotheclosestmultipleof10tothepowerminusn;iftwomultiplesareequallycl

56、ose,roundingisdoneawayfrom0(so.forexample,round(0.5)is1.0andround(-0.5)is-1.0).61 .去重，但是不改变原始数据set(iterable)iterable . The set type is described inReturnanewset,optionallywithelementstakenfromSetTypesset,frozenset.62 .setattr(object,name,value)Thisisthecounterpartofgetattr().Theargumentsareanobject,

57、astringandanarbitraryvalue.Thestringmaynameanexistingattributeoranewattribute.Thefunctionassignsthevaluetotheattribute,providedtheobjectallowsit.Forexample,setattr(x,'foobar',123)isequivalenttox.foobar=123.63 .切片起始位置，终止位置，步长slice(start,stop,step)Returnasliceobjectrepresentingthesetofindicess

58、pecifiedbyrange(start,stop,step).ThestartandstepargumentsdefaulttoNone.Sliceobjectshaveread-onlydataattributesstart,stopandstepwhichmerelyreturntheargumentvalues(ortheirdefault).Theyhavenootherexplicitfunctionality;howevertheyareusedbyNumericalPythonandotherthirdpartyextensions.Sliceobjectsarealsogeneratedwhene