Python与Perl的简单比较.ppt

廖海仁2011.9.15,Python与Perl的简单比较,语言简介,Perl,Python,由C/sed/awk/shell演化而来适合文本处理、系统管理，不适合操作系统开发、多线程编程,从ABC语言继承而来，主要受Modula-3影响，结合Unixshell与C的习惯面向对象、解释性、胶水语言,优点,Perl,Python,强大的正则表达式匹配功能复杂灵活的数据结构Unicode支持(相对AWK/C)自然语言（也是缺点）智能语言（也是缺点）,简单、易学高层语言可移植性面向对象规范的代码（可读性强）图形功能（GUI)数值计算功能(NumPy),缺点,Perl,Python,自然语言，代码晦涩难懂智能语言，可能产生臆断，编程陷阱多不是很优美，很多方法做事，有时让编程者无所适从动态类型语言，不是很可靠，性能问题不适合多线程、底层编程、GUI编程易学难精,强行缩进运行速度不够快（比较编译型语言）动态语言、解释型语言，调试困难（Perl不完全是解释型的）,创始人,LarryWall(Perl)LarryWall,GuidovanRossum(Python),Languist(语言学家）PerlManywaystoaccompanythesametaskConstructsinteractincontext-sentitiveandsometimesquitesubtlewaysmushlikenaturallanguage,Mathematician（数学家）Python:HighdegreeofuniformityOrthogonaldesign,设计理念,DesignPrincipleofPerl,ZenofPython(TimPeters),TheresMoreThanOneWayToDoItEasythingsshouldbeeasy,andhardthingsshouldbepossible,Beautifulisbetterthanugly.Explicitisbetterthanimplicit.Simpleisbetterthancomplex.Complexisbetterthancomplicated.Flatisbetterthannested.Sparseisbetterthandense.Readabilitycounts.Specialcasesarentspecialenoughtobreaktherules.Althoughpracticalitybeatspurity.Errorsshouldneverpasssilently.Unlessexplicitlysilenced.Inthefaceofambiguity,refusethetemptationtoguess.Thereshouldbeone-andpreferablyonlyone-obviouswaytodoit.AlthoughthatwaymaynotbeobviousatfirstunlessyoureDutch.Nowisbetterthannever.Althoughneverisoftenbetterthan*right*now.Iftheimplementationishardtoexplain,itsabadidea.Iftheimplementationiseasytoexplain,itmaybeagoodidea.Namespacesareonehonkinggreatidea-letsdomoreofthose!,Fundamentalprinciplesofhumanlanguage(I),ExpressivenessismoreimportantthanlearnabilityItsquiteOKtospeakin“babytalk”ifyouhappentobeababyAlanguagecanbeusefulevenbeforeyouhavelearnedthewholelanguageThereareoftenseveralgoodwaystosayroughlythesamethingEverylinguisticutterancegetsmeaningfrommanycontextsatonceEffiicentcommunicationrequiresacertainamountoflinguisticcomplexitySemanticnetworksdonotgennerallymapwellintoorthogonalspacesShortcutsabound;commonexpressionsshouldbeshorterthanuncommonexpressions,Fundamentalprinciplesofhumanlanguage(II),Noteverythingcanbeeasytoexpress;itsOKifsomethingsarehardbutpossibleLanguagesarenaturallypunctuatedbypauses,intonation,stress,pacing,etc.HealthycultureismoreimportantthanspecifictechnologytoalanguagessuccessItsOKtospeakwithanaccentaslongasyoucanmakeyourselfunderstoodForanylivinglanguage,evolutionisnotpreventableoverthelongtermItsparticularlyimportantforwrittendocumentstobeevaluatedinhistoricalcontext.,PerlorPython?,Perl拥护者,Python拥护者,正则匹配的近乎完美语言,YoucandoeverythinginPythonthatyoucaninPerl,butyoucanreadyourcodeafteryoudoit简单易学,Perl6VsPython3,Perl6,Python3,Resignofthewholelanguage,Notatotalrewriteoratotalresign,thoughabreakwithbackwardcompatibility,DataStructures,Perl,Python,ScalarsArraysHashes（Perltreateverythingasmutable),NumbersStringsListsDictionaries/SetsTuples(ImmutableLists),关于Python的两个问题,数值与字符串（对应Perl