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1、3DataInputYoucangetnumbersintoRthroughthekeyboard,fromtheClipboardorfromanexternalfile.Forasinglevariableofupto10numbersorso,itisprobablyquickesttotypethenumbersatthecommandline,usingtheconcatenatefunctionclikethis:y<-c(6,7,3,4,8,5,6,2)Forintermediatesizedvariables,youmightwanttoenterdatafromth
2、ekeyboardusingthescanfunction.Forlargerdatasets,andcertainlyforsetswithseveralvariables,youshouldmakeadataframeexternally(e.g.inaspreadsheet)andreaditintoRusingread.table(p.139).3.1DatainputfromthekeyboardThescanfunctionisusefulifyouwanttotype(orpaste)afewnumbersintoavectorcalledxfromthekeyboa
3、rd:x<-scan()1:Atthe1:prompttypeyourfirstnumber,thenpresstheEnterkey.Whenthe2:promptappears,typeinyoursecondnumberandpressEnter,andsoon.Whenyouhaveputinallthenumbersyouneed(supposethereareeightofthem)thensimplypresstheEnterkeyatthe9:prompt.1:62:73:34:45:86:57:68:29:Read8itemsTheRBook,SecondEditi
4、on.MichaelJ.Crawley.©2013JohnWiley&Sons,Ltd.Published2013byJohnWiley&Sons,Ltd.138THERBOOKYoucanalsousescantopasteincolumnsofnumbersfromtheClipboard.Inthespreadsheet,highlightthecolumnofnumbersyouwant,thentypeCtrl+C(theacceleratorkeysforCopy).NowgobackintoR.Atthe1:promptjusttypeCtrl+V(theaccele
5、ratorkeysforPaste)andthenumberswillbescannedintothenamedvariable(xinthisexample).Youcanthenpasteinanothersetofnumbers,orpressReturntocompletedataentry.IfyoutrytoreadinagroupofnumbersfromarowofcellsinExcel,thecharacterswillbepastedintoasinglemulti-digitnumber(definitelynotwhatislikelytohavebeeni
6、ntended).So,ifyouaregoingtopastenumbersfromExcel,makesurethenumbersareincolumns,notinrows,inthespreadsheet.Ifnecessary,useEdit/PasteSpecial/TransposeinExceltoturnarowintoacolumnbeforecopyingthenumbers.3.2DatainputfromfilesTheeasiestwaytogetdataintoRistomakeyourdataintotheshapeofadataframebefore
7、tryingtoreaditintoR.AsexplainedindetailinChapter4,youshouldputallofthevaluesofeachvariableintoasinglecolumn,andputthenameofthevariableinrow1(calledthe‘header’row).Youwillsometimesseetherowsandthecolumnsofthedataframereferredtoascasesand
