python函數(shù)中文手冊(cè)

1、內(nèi)置函數(shù)一，文檔說(shuō)明原始文檔來(lái)自于pythonv2.7.2中文譯文和用法尚不完全，您可以自由修改和完善，您可以在文檔結(jié)尾鳴謝添上您的名字，我們將會(huì)感謝您做的貢獻(xiàn)！二，函數(shù)列表1,取絕對(duì)值abs(x)Returntheabsolutevalueofanumber.Theargumentmaybeaplainorlongintegerorafloatingpointnumber.Iftheargumentisacomplexnumber,itsmagnitudeisreturned.如果你不知道絕對(duì)值什么意思，那就要補(bǔ)一下小學(xué)數(shù)學(xué)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).是字符串和字符編碼的超類(lèi)，是抽象類(lèi)型。不能被調(diào)用或者實(shí)例化?？梢杂脕?lái)判斷實(shí)例是否為字符申或者字符編碼。方法:5 .二進(jìn)制轉(zhuǎn)換bin(x)Convertanintegernumbertoabinarystring.TheresultisavalidPythonexpression.IfxisnotaPythonin£object,ithastodefineanindex()methodthatr

4、eturnsaninteger.轉(zhuǎn)換成二進(jìn)制表達(dá)方法:6 .布爾類(lèi)型bool(x)ConvertavaluetoaBoolean,usingthestandardtruthtestingprocedure.Ifxisfalseoromitted,thisreturnsFalse;otherwiseitreturnsTrue.boolisalsoaclass,whichisasubclassofint.Classboolcannotbesubclassedfurther.ItsonlyinstancesareFalseandTrue布爾類(lèi)型的轉(zhuǎn)化用法:7 .二進(jìn)制數(shù)組的轉(zhuǎn)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.數(shù)字轉(zhuǎn)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 .兩兩比較cmp(x,y)Comparethetw

10、oobjectsxandyandreturnanintegeraccordingtotheoutcome.Thereturnvalueisnegativeifx<y,zeroifx=yandstrictlypositiveifx>y.X小于X輸出負(fù)(-1),X等于Y輸出零(0),X大于Y輸出正(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 .很重要的函數(shù)，屬性輸出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很相似的函數(shù)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.浮點(diǎn)數(shù)值轉(zhuǎn)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 .全局參數(shù)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. 很重要的幫助函數(shù)方法help(object)31. 十六進(jìn)制轉(zhuǎn)化hex(x)Convertanintegernumber(ofanysize)toahexadecimalstr

28、ing.TheresultisavalidPythonexpression.用法：32. 內(nèi)存地址id(object)Returnthe“identity“ofanobject.Thisisaninteger(orlonginteger)whichisguaranteedtobeuniqueandconstantforthisobjectduringitslifetime.Twoobjectswithnon-overlappinglifetimesmayhavethesameid()value.如果想知道某個(gè)對(duì)象的內(nèi)存地址，用這個(gè)內(nèi)置函數(shù)，返回的是10進(jìn)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. 導(dǎo)管，窗口，容器，數(shù)據(jù)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)返回一個(gè)迭代器對(duì)象。第一個(gè)參數(shù)根據(jù)第二個(gè)參數(shù)進(jìn)行編譯。第二參數(shù)為空，。必須是支持迭代器的協(xié)議(the_iter_()method)的集合對(duì)象，或者支持順序協(xié)議(the_getitem_()methodwithintegerargumentsstaringat0).如果不支持其中任意一種協(xié)議，程序?qū)?huì)拋出類(lèi)型異常。假如第二個(gè)參數(shù)被給出，然后O必須是一個(gè)可被調(diào)用的對(duì)象。迭代器被創(chuàng)建

37、萬(wàn)一will掉用Owith沒(méi)有參數(shù)foreachcalltoitsnext()method;如果返回值和初始值相同l,StopIteration將會(huì)拋出,否則值會(huì)被返回！38. 計(jì)算長(zhǎng)度(常用函數(shù))len(s)Returnthelength(thenumberofitems)ofanobject.Theargumentmaybeasequence(string,tupleorlist)oramapping(dictionary).用法：39. 轉(zhuǎn)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兒key)Withasingleargumentiterable,returnthesmallestitemofanon-emptyiterable(suchasastring,tupleorlist).Withmorethanoneargument,returnthesmall

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

46、llinstancesofnewstyleclasses.48 .八進(jìn)制字符串的轉(zhuǎn)化oct(x)Convertanintegernumber(ofanysize)toanoctalstring.TheresultisavalidPythonexpression.用法:49 .open(filename,mode,bufsize)Openafile,returninganobjectofthefiletypedescribedinsectionFileObjects.Ifthefilecannotbeopened,IOErrorisraised.Whenopeningafile,it's

47、preferpenOouseinsteadofinvokingthefileconstructordirectly.50 .字符轉(zhuǎn)化成ASCn碼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函數(shù)原來(lái)本身就是函數(shù)。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，終止位置，步長(zhǎng)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. 重載模塊，很重要的函數(shù)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，但是不改變?cè)紨?shù)據(jù)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，終止位置，步長(zhǎng)slice(start,stop,step)Returnasliceobjectrepresentingthesetofindicess

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