smu_2010_perl_l01

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1、PERL(I)WhatisPerlPerlisacleverlittleprogramminglanguagePerl-----PracticalExtractionandReportLanguagePerlhasthepowerandflexibilityofahigh-levelprogramminglanguagesuchasC.Perl'ssyntaxresemblesC.Perlallowstheeasymanipulationoffiles,processtextinformation,

2、andmanyotheritems.WhyPerl?Perldoesnotrequireaspecialcompilertoturntheprogramsyouwriteintoworkingcode.Instead,allyouhavetodoiswritetheprogramandtellPerltorunit.Perlisfree.PerliswidelyandintensivelyusedinbioinformaticstohandleDNAandProteinsequencesaswell

3、asindevelopingofwebbasedinteractivebioinformaticsapplications.PerliseasiertolearnthanCInterpretiveLanguagesVs.CompiledLanguagesLanguagessuchasPerlthatareprocessedbyaninterpreterareknownasinterpretivelanguages.Example:Perl,HTML,Javascipt,PHP,etc.Foracom

4、piledlanguage,theprogramyouwritemustbetranslatedintomachine-readablecodebyaspecialprogramknownasacompiler.Inaddition,librarycodemightneedtobeaddedbyanotherspecialprogramknownasalinker.Example:C/C++,Java,Fortran,Basic,Pascal,etc.AdvantagesandDisadvantag

5、esItisveryeasytorunaprograminaninterpretivelanguagelikePerlPerlismuchmoreefficientthanotherprogramminglanguageinprocessingbiologicalsequencedata.Givenacomputationintensivejob,acompiledprogramisingeneralmuchfasterthanainterpretiveprogram.InstallingPerlD

6、oYouHavePerlInstalled?GotoaDOSorUnixcommand-linepromptandtype:perl-vInstallingPerlonyourPChttp://www.activestate.com/Products/Download/Register.plex?id=ActivePerlDownloadActivePerlforMS-WindowsfromandinstallitinyourPCCreatingaPerlprogramAPerlprogramcon

7、sistsofanordinarytextfile(plaintextfile)containingaseriesofPerlstatements.APerlProgramhasafilenamewithsuffix.plYouneedatexteditortocreatePerlprograms.Recommendation:UltraEditforPCWindows(http://www.ultraedit.com)WindowsNotepadalsoOK.invokingaPerlprogra

8、mUnderDOSorUnixcommandlinepromptgotothedirectorywhereyourPerlprogramisandtypeperlmyprogram.plPERLsyntaxAPerlprogramiscomprisedofstatementsCommentsbeginwithapoundsign(#)Perlstatementsmustendinasemicolon(;)Examplecode:#thisisashortexample