python函数中文手册.docx

python函数中文手册.docx

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python函数中文手册

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）

ReturnTrueifallelementsoftheiterablearetrue（oriftheiterableisempty）.Equivalentto:

3.

any（iterable）

ReturnTrueifanyelementoftheiterableistrue.Iftheiterableisempty,returnFalse.Equivalentto:

4.

basestring（）

Thisabstracttypeisthesuperclassforstrandunicode.Itcannotbecalledorinstantiated,butitcanbeusedtotestwhetheranobjectisaninstanceofstrorunicode.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串或者字符编码。

方法：

5．二进制转换

bin（x）

Convertanintegernumbertoabinarystring.TheresultisavalidPythonexpression.IfxisnotaPythonintobject,ithastodefinean__index__（）methodthatreturnsaninteger.

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（[source[,encoding[,errors]]]）

Returnanewarrayofbytes.Thebytearraytypeisamutablesequenceofintegersintherange0<=x<256.Ithasmostoftheusualmethodsofmutablesequences,describedinMutableSequenceTypes,aswellasmostmethodsthatthestrtypehas,seeStringMethods.

Theoptionalsourceparametercanbeusedtoinitializethearrayinafewdifferentways:

Ifitisastring,youmustalsogivetheencoding（andoptionally,errors）parameters;bytearray（）thenconvertsthestringtobytesusing（）.

Ifitisaninteger,thearraywillhavethatsizeandwillbeinitializedwithnullbytes.

Ifitisanobjectconformingtothebufferinterface,aread-onlybufferoftheobjectwillbeusedtoinitializethebytesarray.

Ifitisaniterable,itmustbeaniterableofintegersintherange0<=x<256,whichareusedastheinitialcontentsofthearray.

Withoutanargument,anarrayofsize0iscreated.

8.

callable（object）

ReturnTrueiftheobjectargumentappearscallable,Falseifnot.Ifthisreturnstrue,itisstillpossiblethatacallfails,butifitisfalse,callingobjectwillneversucceed.Notethatclassesarecallable（callingaclassreturnsanewinstance）;classinstancesarecallableiftheyhavea__call__（）method.

9.数字转化成字符

chr（i）

ReturnastringofonecharacterwhoseASCIIcodeistheintegeri.Forexample,chr（97）returnsthestring'a'.Thisistheinverseoford（）.Theargumentmustbeintherange[0..255],inclusive;ValueErrorwillberaisedifiisoutsidethatrange.Seealsounichr（）.

用法：

10.

classmethod（function）

Returnaclassmethodforfunction.

Aclassmethodreceivestheclassasimplicitfirstargument,justlikeaninstancemethodreceivestheinstance.Todeclareaclassmethod,usethisidiom:

11.两两比较

cmp（x,y）

Comparethetwoobjectsxandyandreturnanintegeraccordingtotheoutcome.Thereturnvalueisnegativeifxy.

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.Codeobjectscanbeexecutedbyanexecstatementorevaluatedbyacalltoeval（）.sourcecaneitherbeastringoranASTobject.RefertotheastmoduledocumentationforinformationonhowtoworkwithASTobjects.

13.

complex（[real[,imag]]）

Createacomplexnumberwiththevaluereal+imag*jorconvertastringornumbertoacomplexnumber.Ifthefirstparameterisastring,itwillbeinterpretedasacomplexnumberandthefunctionmustbecalledwithoutasecondparameter.Thesecondparametercanneverbeastring.Eachargumentmaybeanynumerictype（includingcomplex）.Ifimagisomitted,itdefaultstozeroandthefunctionservesasanumericconversionfunctionlikeint（）,long（）andfloat（）.Ifbothargumentsareomitted,returns0j.

14.

delattr（object,name）

Thisisarelativeofsetattr（）.Theargumentsareanobjectandastring.Thestringmustbethenameofoneoftheobject’sattributes.Thefunctiondeletesthenamedattribute,providedtheobjectallowsit.Forexample,delattr（x,'foobar'）isequivalenttodel.

15．字典

dict（[arg]）

Createanewdatadictionary,optionallywithitemstakenfromarg.ThedictionarytypeisdescribedinMappingTypes—dict.

Forothercontainersseethebuiltinlist,set,andtupleclasses,andthecollectionsmodule.

16.很重要的函数，属性输出

dir（[object]）

Withoutarguments,returnthelistofnamesinthecurrentlocalscope.Withanargument,attempttoreturnalistofvalidattributesforthatobject.

方法

17.

divmod（a,b）

Taketwo（noncomplex）numbersasargumentsandreturnapairofnumbersconsistingoftheirquotientandremainderwhenusinglongdivision.Withmixedoperandtypes,therulesforbinaryarithmeticoperatorsapply.Forplainandlongintegers,theresultisthesameas（aForfloatingpointnumberstheresultis（q,a%b）,whereqisusually（a/b）butmaybe1lessthanthat.Inanycaseq*b+a%bisveryclosetoa,ifa%bisnon-zeroithasthesamesignasb,and0<=abs（a%b）

18.

enumerate（sequence[,start=0]）

Returnanenumerateobject.sequencemustbeasequence,aniterator,orsomeotherobjectwhichsupportsiteration.Thenext（）methodoftheiteratorreturnedbyenumerate（）returnsatuplecontainingacount（fromstartwhichdefaultsto0）andthecorrespondingvalueobtainedfromiteratingoveriterable.enumerate（）isusefulforobtaininganindexedseries:

（0,seq[0]）,（1,seq[1]）,（2,seq[2]）

19.

eval（expression[,globals[,locals]]）

Theargumentsareastringandoptionalglobalsandlocals.Ifprovided,globalsmustbeadictionary.Ifprovided,localscanbeanymappingobject.

Changedinversion:

formerlylocalswasrequiredtobeadictionary.

20.

execfile（filename[,globals[,locals]]）

Thisfunctionissimilartotheexecstatement,butparsesafileinsteadofastring.Itisdifferentfromtheimportstatementinthatitdoesnotusethemoduleadministration—itreadsthefileunconditionallyanddoesnotcreateanewmodule.

和exec很相似的函数

21.

file（filename[,mode[,bufsize]]）

Constructorfunctionforthefiletype,describedfurtherinsectionFileObjects.Theconstructor’sargumentsarethesameasthoseoftheopen（）built-infunctiondescribedbelow.

Whenopeningafile,it’spreferabletouseopen（）insteadofinvokingthisconstructordirectly.fileismoresuitedtotypetesting（forexample,writingisinstance（f,file））.

22.

filter（function,iterable）

Constructalistfromthoseelementsofiterableforwhichfunctionreturnstrue.iterablemaybeeitherasequence,acontainerwhichsupportsiteration,oraniterator.Ifiterableisastringoratuple,theresultalsohasthattype;otherwiseitisalwaysalist.IffunctionisNone,theidentityfunctionisassumed,thatis,allelementsofiterablethatarefalseareremoved.

Notethatfilter（function,iterable）isequivalentto[itemforiteminiterableiffunction（item）]iffunctionisnotNoneand[itemforiteminiterableifitem]iffunctionisNone.

See（）and（）foriteratorversionsofthisfunction,includingavariationthatfiltersforelementswherethefunctionreturnsfalse.

23.浮点数值转化

float（[x]）

用法：

24.

format（value[,format_spec]）

Convertavaluetoa“formatted”representation,ascontrolledbyformat_spec.Theinterpretationofformat_specwilldependonthetypeofthevalueargument,howeverthereisastandardformattingsyntaxthatisusedbymostbuilt-intypes:

FormatSpecificationMini-Language.

25

frozenset（[iterable]）

Returnafrozensetobject,optionallywithelementstakenfromiterable.ThefrozensettypeisdescribedinSetTypes—set,frozenset.

Forothercontainersseethebuiltindict,list,andtupleclasses,andthecollectionsmodule.

26.

getattr（object,name[,default]）

Returnthevalueofthenamedattributeofobject.namemustbeastring.Ifthestringisthenameofoneoftheobject’sattributes,theresultisthevalueofthatattribute.Forexample,getattr（x,'foobar'）isequivalentto.Ifthenamedattributedoesnotexist,defaultisreturnedifprovided,otherwiseAttributeErrorisraised.

27.全局参数

globals（）

Returnadictionaryrepresentingthecurrentglobalsymboltable.Thisisalwaysthedictionaryofthecurrentmodule（insideafunctionormethod,thisisthemodulewhereitisdefined,notthemodulefromwhichitiscalled）.

28.

hasattr（object,name）

Returnthehashvalueoftheobject（ifithasone）.Hashvaluesareintegers.Theyareusedtoquicklycomparedictionarykeysduringadictionarylookup.Numericvaluesthatcompareequalhavethesamehashvalue（eveniftheyareofdifferenttypes,asisthecasefor1and.

29.

hash（object）

Returnthehashvalueoftheobject（ifithasone）.Hashvaluesareintegers.Theyareusedtoquicklycomparedictionarykeysduringadictionarylookup.Numericvaluesthatcompareequalhavethesamehashvalue（eveniftheyareofdifferenttypes,asisthecasefor1and.

30.很重要的帮助函数方法

help（[object]）

31.十六进制转化

hex（x）

Convertanintegernumber（ofanysize）toahexadecimalstring.TheresultisavalidPythonexpression.

用法：

32.内存地址

id（object）

Returnthe“identity”ofanobject.Thisisaninteger（orlonginteger）whichisguaranteedtobeunique