R Programming LanguageR程式語言課件

RProgrammingLanguage

R林建甫C.F.JeffLin,MD.PhD.臺北大學統(tǒng)計系助理教授臺北榮民總醫(yī)院生物統(tǒng)計顧問美國密西根大學生物統(tǒng)計博士3/24/20231JeffLin,MD.PhD.******R:物件導向程式語言

RasObjective-OrientedLanguage3/24/20232JeffLin,MD.PhD.******R:基本(RBasics)物件命名與指派(NamingandAssign)變數(shù)類型(TypeofVariables)缺失值(MissingValues)資料輸入與指派(AssignmentandInputData)函數(shù)(Functions)工作路徑(Workspace)歷史紀錄(History)3/24/20233JeffLin,MD.PhD.******物件指派＜－指派＝(避免使用)>xyz.vector＜－c(1,2,3)3/24/20235JeffLin,MD.PhD.******物件Objects物件名稱(names)物件種類(TypeofVariables):向量,因子,陣列,矩陣,資料框架,時間序列,列表.(vector,factor,array,matrix,data.frame,ts,list)屬性(attributes)模式(mode):邏輯,整數(shù),倍精準度,單精準度,複數(shù),文字.(numeric,character,complex,logical)長度(Length):與物件的模式有關物件產(chǎn)生(creation):指派數(shù)值或空物件3/24/20237JeffLin,MD.PhD.******>a<-49>sqrt(a)[1]7>b<-"Thedogatemyhomework">sub("dog","cat",b)[1]"Thecatatemyhomework">x<-(1+1==3)>x[1]FALSE>as.character(b)[1]"FALSE"數(shù)值numeric文字與字串characterstring邏輯

logical基本模式變數(shù)命名與指派3/24/20238JeffLin,MD.PhD.******物件指派Assignment“<-”usedtoindicateassignment>x<-c(1,2,3,4,5,6,7)>x<-c(1:7)>x<-1:43/24/202310JeffLin,MD.PhD.******3/24/202311JeffLin,MD.PhD.******R:邏輯操作與關係比較操作== Equalto!= Notequalto< Lessthan> Greaterthan<= Lessthanorequalto>= Greaterthanorequaltois.na(x) Missing?& LogicalAND| LogicalOR! LogicalNOT3/24/202313JeffLin,MD.PhD.******缺失值NA,NaN,與NullNA或“NotAvailable”可用在許多模式(modes)–character,numeric,etc.NaN或“NotaNumber”只用在數(shù)值模式(numericmodes)NULL列表(lists)的長度為0(zerolength)3/24/202314JeffLin,MD.PhD.******缺失值MissingValuesNA“notavailable”

>x<-c(1,2,3,NA) >x+3

[1]456NA非數(shù)字“Notanumber” >log(c(0,1,2))

[1]-Inf0.00000000.6931472 >0/0

[1]NaN3/24/202316JeffLin,MD.PhD.******R:缺失值MissingValuesNA或“NotAvailable”NA不是0NA不是““(空格,或空字串)NA不是FALSE任何與NA的計算,可能或不可能產(chǎn)生NA>1+NA[1]NA>max(c(NA,4,7))[1]NA>max(c(NA,4,7),na.rm=T)[1]73/24/202317JeffLin,MD.PhD.******TypesofObjects向量Vector矩陣Matrix陣列Array列表List因子Factor時間序列Timeseries資料框架Dataframe函式Function>typeof(物件名稱)可已回傳物件型態(tài)3/24/202319JeffLin,MD.PhD.******Mode物件結構(模式)模式Mode原型模式AtomicMode: logical,numeric,complex或character遞迴型RecursiveModelist,graphics,function,expression,call..>mode()指令可以用來查看物件的模式3/24/202320JeffLin,MD.PhD.******物件長度(Length)長度Lengthvector:numberofelementsmatrix,array:productofdimensionslist:numberofcomponentsdataframe:numberofcolumns3/24/202321JeffLin,MD.PhD.******物件屬性(Attribute)屬性Attributes列位名(rowname),欄位名(columnname),維度(dimension).>s()>names()>str()3/24/202322JeffLin,MD.PhD.******向量Vector指包含相同``模式''的元素(element)組成序列.主要有6種基本模式(mode)logical,integer,double,single,complex,andcharacter.(邏輯,整數(shù),倍精準度,單精準度,複數(shù),文字).向量是具有相同基本類型的元素序列,大體相當於其他語言中的1-維度數(shù)列,在R中,單一數(shù)值(scalar)也可看成是長度為1的向量.3/24/202324JeffLin,MD.PhD.******向量Vector>a<-c(1,2,3)>a*2[1]246向量的產(chǎn)生最常用辦法是使用函式c(),它把若干個數(shù)值或字串組合為一個向量,3/24/202325JeffLin,MD.PhD.******向量運算操作算數(shù)操作(arithmeticoperator)符號包含+,-,*,/,^,%%,%/%,%*%,%o%,%x%等.通常其含意是對向量的每一個元素進行運算的``單元運算子''(unary)或``二元運算子''(binary),如同一般算數(shù)運用在向量.向運有“長度”,但不具有“維度”.3/24/202326JeffLin,MD.PhD.******向量Vectors>Mydata<-c(2,3.5,-0.2) #>Colors<-c(“Red”,“Green”,“Red”) #文字>x1<-25:30>x1[1]252627282930 #數(shù)字序列>Colors[2][1]“Green”

#單一元素>x1[3:5][1]272829

#多各元素3/24/202327JeffLin,MD.PhD.******3/24/202329JeffLin,MD.PhD.******3/24/202330JeffLin,MD.PhD.******向量Vectors

>x<-c(5.2,1.7,6.3) >log(x)

[1]1.64865860.53062831.8405496

>y<-1:5 >z<-seq(1,1.4,by=0.1) >y+z [1]2.06.4

>length(y) [1]5

>mean(y+z) [1]4.23/24/202331JeffLin,MD.PhD.******3/24/202332JeffLin,MD.PhD.******向量運算操作邏輯檢測抽出某一元素刪除元素>Mydata[1]23.5-0.2

>Mydata>0[1]TRUETRUEFALSE >Mydata[Mydata>0][1]23.5

>Mydata[-c(1,3)][1]3.5

3/24/202333JeffLin,MD.PhD.******向量運算操作>x<-c(5,-2,3,-7) >y<-c(1,2,3,4)*10 #對所有元素操作>y[1]10203040>sort(x) #重新排序[1]-7-235>order(x)[1]4231

#排順序後的位置>y[order(x)][1]40203010 #>rev(x) #反向[1]-73-253/24/202334JeffLin,MD.PhD.******c()&rev()>c(1,3,5,7)[1]1357>rev(c(1,3,5,7))[1]75313/24/202335JeffLin,MD.PhD.******length(),mode()&names()>x<-c(1,3,5,7)>length(x)[1]4>mode(x)[1]"numeric">names(x)NULL3/24/202336JeffLin,MD.PhD.******seq()seq()產(chǎn)生數(shù)字序列>seq(1:5)[1]12345>seq(5,1,by=-1)[1]54321>seq(5)[1]123453/24/202337JeffLin,MD.PhD.******seq()>1.1:5[1]4.1>4:-5[1]43210-1-2-3-4-5>seq(-1,2,0.5)[1]-1.0-0.50.00.51.01.52.0>seq(1,by=0.5,length=5)[1]1.01.52.02.53.03/24/202338JeffLin,MD.PhD.******rep()rep()replicateselements>rep(1,5)[1]11111>rep(1:2,3)[1]121212>rep(1:2,each=3)[1]111222>rep(1:2,each=3,len=4)[1]1112>rep(1:2,each=3,len=7)[1]1112221>rep(1:2,each=3,time=2)[1]1112221112223/24/202339JeffLin,MD.PhD.******sort()&rank()>x<-c(8,6,9,7)>sort(x)[1]6789>rank(x)[1]3142>rank(x)[1][1]3>x[rank(x)==1][1]6>x[rank(x)][1]98763/24/202340JeffLin,MD.PhD.******rank()&order()>x<-c(8,6,9,7)>order(x)[1]2413>rank(x)[1]3142>x[order(x)][1]6789>x[rank(x)][1]98763/24/202341JeffLin,MD.PhD.******矩陣Matrix矩陣由包含相同的元素組成的2-維(2-dimension)資料物件可由matrix()產(chǎn)生>x<-matrix(data=0,nr=2,nc=2)>x<-matrix(0,2,2)3/24/202342JeffLin,MD.PhD.******矩陣下標

>x<-c("a","b","c","d","e","f","g","h") >x[1] >x[3:5] >x[-(3:5)] >x[c(T,F,T,F,T,F,T,F)] >x[x<="d"] >m[,2] >m[3,]3/24/202343JeffLin,MD.PhD.******GenerateaMatrix>xmat<-matrix(1:12,nrow=3,byrow=T)>xmat[,1][,2][,3][,4][1,]1234[2,]5678[3,]9101112>length(xmat)[1]12>dim(xmat)[1]34>mode(xmat)[1]"numeric">names(xmat)NULL>dimnames(xmat)NULL3/24/202344JeffLin,MD.PhD.******GenerateaMatrix>matrix(0,3,3)[,1][,2][,3][1,]000[2,]000[3,]0003/24/202345JeffLin,MD.PhD.******GenerateaMatrix>dimnames(xmat)<-list(c("A","B","C"),c("W","X","Y","Z"))>dimnames(xmat)[[1]][1]"A""B""C"[[2]][1]"W""X""Y""Z">xmatWXYZA1234B5678C91011123/24/202346JeffLin,MD.PhD.******DiagonalElementofaMatrix>m<-matrix(1:12,4,byrow=T)>m[,1][,2][,3][1,]123[2,]456[3,]789[4,]101112>diag(m)[1]1593/24/202347JeffLin,MD.PhD.******DiagonalElementofaMatrix>diag(k)[,1][,2][,3][1,]100[2,]010[3,]0013/24/202348JeffLin,MD.PhD.******InverseofMatrices>m<-matrix(c(1,3,5,,9,11,13,15,19,21),3,byrow=T)>m[,1][,2][,3][1,]135[2,]91113[3,]151921>solve(m)[,1][,2][,3][1,]-0.50001.0000-0.5[2,]0.1875-1.68751.0[3,]0.18750.8125-0.53/24/202349JeffLin,MD.PhD.******rbind()&cbind()>x<-c(1,2,3)>y<-matrix(0,3,3)>rbind(y,x)[,1][,2][,3]000000000x123>cbind(y,x)x[1,]0001[2,]0002[3,]00033/24/202350JeffLin,MD.PhD.******Multiplication>x<-matrix(1:4,2,byrow=T)>y<-matrix(1:4,2,byrow=T)>x*y#elementwise[,1][,2][1,]14[2,]916>x%*%y#[,1][,2][1,]710[2,]15223/24/202351JeffLin,MD.PhD.******>x%o%x,,1,1[,1][,2][1,]12[2,]34,,2,1[,1][,2][1,]36[2,]912,,1,2[,1][,2][1,]24[2,]68,,2,2[,1][,2][1,]48[2,]12163/24/202352JeffLin,MD.PhD.******ArrayArraysaregeneralizedmatricesbyextendingthefunctiondim()tomorthantwodimensions.>xarr<-array(c(1:8,11:18,111:118),dim=c(2,4,3))#row,col,array>xarr,,1[,1][,2][,3][,4][1,]1357[2,]2468,,2[,1][,2][,3][,4][1,]11131517[2,]12141618,,3[,1][,2][,3][,4][1,]111113115117[2,]1121141161183/24/202353JeffLin,MD.PhD.******列表Lists3/24/202354JeffLin,MD.PhD.******列表Lists列表是一個特殊的``向量'',這特殊的向量中的元素是物件.因此列表物件是由資料物件有順序組成,列表物中的``元素'',稱作``成份''(component)是物件本身.是有順序的(ordersequence).成份物件的元素模式,沒有任合限制,每一個別成份的物件之原型模式可以不相同.3/24/202355JeffLin,MD.PhD.******列表Lists>doe<-list(name="john",age=28,married=F)>doe$name[1]"john“>doe$age[1]28>doe[[3]][1]FALSE列表由“$”抽取元素3/24/202356JeffLin,MD.PhD.******列表Listsvector:

指包含相同``模式''的元素(element)組成序列.>a=c(7,5,1)>a[2][1]5list:列表是一個特殊的``向量'',這特殊的向量中的元素是物件.

>doe=list(name="john",age=28,married=F)>doe$name[1]"john“>doe$age[1]283/24/202357JeffLin,MD.PhD.******列表Lists>my.list<-list(c(5,4,-1),c("X1","X2","X3"))>my.list[[1]]:[1]54-1[[2]]:[1]"X1""X2""X3">my.list[[1]][1]54-1>my.list<-list(c1=c(5,4,-1),c2=c("X1","X2","X3"))>my.list$c2[2:3][1]"X2""X3"3/24/202358JeffLin,MD.PhD.******列表Lists>x.mat

[,1][,2][1,]3-1[2,]20[3,]-36>dimnames(x.mat)<-list(c("L1","L2","L3"),c("R1","R2"))>x.matR1R2L13-1L220L3-363/24/202359JeffLin,MD.PhD.******Lists,FactorsandDataFrames3/24/202360JeffLin,MD.PhD.******因數(shù)或因子Factorandfactor()處理類別資料,提供的一種有效的方法.因為統(tǒng)計中的離散變數(shù)(discretevariable)名義變數(shù)(nominalvariable)與有序變數(shù)(ordinalvariable).因素/因子是一種特殊的文字向量,文字向量中每一個元素,取一個離散值.因素物件有一個特殊屬性層次/水平/水準(levels)表示這組所有的離散值.因數(shù)可以簡單地用函式factor()產(chǎn)生.因素/因子是用``文字/字串‘’輸入,一但設定為因素/因子向量,{R}列印時,並不會加上雙引號{"}.3/24/202361JeffLin,MD.PhD.******因數(shù)或因子Factorandfactor()>gender<-c("male","female","male","male","female","female")>gender[1]"male""female""male""male""female""female">factor(gender)[1]malefemalemalemalefemalefemaleLevels:femalemale3/24/202362JeffLin,MD.PhD.******factor()andlevels()intensity<-factor(c("Hi","Med","Lo","Hi","Lo","Med", "Lo","Hi","Med"))>intensity[1]HiMedLoHiLoMedLoHiMedLevels:HiLoMed3/24/202363JeffLin,MD.PhD.******factor()andlevels()>intensity<-factor(c("Hi","Med","Lo","Hi","Lo","Med","Lo","Hi","Med"),levels=c("Hi","Med","Lo"))>intensity[1]HiMedLoHiLoMedLoHiMedLevels:HiMedLo3/24/202364JeffLin,MD.PhD.******factor()andlevels()intensity<-factor(c("Hi","Med","Lo","Hi","Lo","Med", "Lo","Hi","Med"),levels=c("Hi","Med","Lo"),labels=c("HiDOse","MedDOse","LoDose"))>intensity[1]HiDOseMedDOseLoDoseHiDOseLoDoseMedDOseLoDoseHiDOseMedDOseLevels:HiDOseMedDOseLoDose3/24/202365JeffLin,MD.PhD.******factor(),ordered()andlevels()intensity<-ordered(c("Hi","Med","Lo","Hi","Lo","Med", "Lo","Hi","Med"))>intensity[1]HiMedLoHiLoMedLoHiMedLevels:Hi<Lo<MedOooooop!Thisisnotwhatyouwant!3/24/202366JeffLin,MD.PhD.******factor(),ordered()andlevels()intensity<-ordered(c("Hi","Med","Lo","Hi","Lo","Med", "Lo","Hi","Med"),levels=c("Lo","Med","Hi"))>intensity[1]HiMedLoHiLoMedLoHiMedLevels:Lo<Med<HiOrdinalVariable!3/24/202367JeffLin,MD.PhD.******Lists,FactorsandDataFrames3/24/202368JeffLin,MD.PhD.******DataFramesdataframe:representsaspreadsheet.Rectangulartablewithrowsandcolumns;datawithineachcolumnhasthesametype(e.g.number,text,logical),butdifferentcolumnsmayhavedifferenttypes....3/24/202369JeffLin,MD.PhD.******DataFrames#RdataToothGrowth#TheEffectofVit.ConToothGrowthinGuineaPigs>ToothGrowthlensuppdose14.2VC0.5211.5VC0.537.3VC0.545.8VC0.5…5827.3OJ2.05929.4OJ2.06023.0OJ2.03/24/202370JeffLin,MD.PhD.******DataFramesAdataframeisalistwithclass“data.frame”.Therearerestrictionsonliststhatmaybemadeintodataframes.a.Thecomponentsmustbevectors(numeric,character,orlogical),factors,numericmatrices,lists,orotherdataframes.b.Matrices,lists,anddataframesprovideasmanyvariablestothenewdataframeastheyhavecolumns,elements,orvariables,respectively.3/24/202371JeffLin,MD.PhD.******DataFrames

c.Numericvectorsandfactorsareincludedasis,andnon-numericvectorsarecoercedtobefactors,whoselevelsaretheuniquevaluesappearinginthevector.d.Vectorstructuresappearingasvariablesofthedataframemustallhavethesamelength,andmatrixstructuresmustallhavethesamerowsize.3/24/202372JeffLin,MD.PhD.******DataFrameseveralmodesallowedwithinasingledataframecanbecreatedusingdata.frame()L<-LETTERS[1:4]#ABCDx<-1:4#1234data.frame(x,L)#createdataframeattach()anddetach()thedatabaseisattachedtotheRsearchpathsothatthedatabaseissearchedbyRwhenitisevaluatingavariable.objectsinthedatabasecanbeaccessedbysimplygivingtheirnames3/24/202373JeffLin,MD.PhD.******DataElementsselectonlyoneelementx[2]selectrangeofelementsx[1:3]selectallbutoneelementx[-3]slicing:includingonlypartoftheobjectx[c(1,2,5)]selectelementsbasedonlogicaloperatorx(x>3)3/24/202374JeffLin,MD.PhD.******Individualelementsofavector,matrix,arrayordataframeareaccessedwith“[]”byspecifyingtheirindex,ortheirname>ToothGrowth[1:3,]lensuppdose14.2VC0.5211.5VC0.57.3VC0.5>ToothGrowth[1:2,1:2]

lensupp14.2VC211.5VCSubsetting3/24/202375JeffLin,MD.PhD.******LabelsinDataFrames>labels(ToothGrowth)[[1]][1]"1""2""3""4""5""6""7""8""9""10""11""12"[13]"13""14""15""16""17""18""19""20""21""22""23""24"[25]"25""26""27""28""29""30""31""32""33""34""35""36"[37]"37""38""39""40""41""42""43""44""45""46""47""48"[49]"49""50""51""52""53""54""55""56""57""58""59""60"[[2]][1]"len""supp""dose"3/24/202376JeffLin,MD.PhD.******Findingoutaboutadataobjectmode():tellsyouthestorage‘mode’ofanobject(i.e.whetheritisanumericvector,oralistetc.)attributes():providesinformationaboutthedataobjectclass():providesinformaitonabouttheobject’sclass.Theclassofanobjectoftendetermineshowthedataobjectishandledbyafunction.Youcanalsosettheobject’smode,attributesorclassusingtheabovefunctions.e.g.mode(x)<-“numeric”3/24/202377JeffLin,MD.PhD.******Whattypeismydata?classClassfromwhichobjectinherits(vector,matrix,function,logical,list,…)modeNumeric,character,logical,…storage.modetypeofModeusedbyRtostoreobject(double,integer,character,logical,…)is.functionLogical(TRUEiffunction)is.naLogical(TRUEifmissing)namesNamesassociatedwithobjectdimnamesNamesforeachdimofarrayslotNamesNamesofslotsofBioCobjectsattributesNames,class,etc.3/24/202378JeffLin,MD.PhD.******DataImport&Entry3/24/202379JeffLin,MD.PhD.******TopicsDatasetsthatcomewithRInputtingdatafromafileWritingdatatoafileWritingdatatotheclipboardExchangingdatabetweenprogramsNB:savingtheworkspace3/24/202380JeffLin,MD.PhD.******Rcomeswithseveralpre-packageddatasets

Youcanaccessthesedatasetswiththedatafunctiondata()

getsyoualistofallthedatasetsdata(Titanic)

loadsadatasetaboutpassengers ontheTitanic(forexample)summary(Titanic)

providessomesummaryinformation aboutthedatasetTitanicattributes(Titanic)providessomemoreinformationTypingthedatasetnameonitsown(followedbyEnter)willdisplaythedata3/24/202381JeffLin,MD.PhD.******Data>summary(data)>names(data)>attributes(data)Editingdata>fix(data)or>edit(data)>data$var>attach(data)#inordertoremoveneedof‘$’>detach(data)3/24/202382JeffLin,MD.PhD.******DataEntry&Editingstarteditorandsavechangesdata.entry(x)starteditor,changesnotsavedde(x)starttexteditoredit(x)3/24/202383JeffLin,MD.PhD.******TheattachanddetachfunctionsTheattachfunctionmakesalltheobjectsinalistordataframeaccessiblefromoutsidethelistordataframe.E.g.insteadoftypingmy_list$agetoaccessthevector‘a(chǎn)ge’inthelistmy_listyoucanjusttype‘a(chǎn)ge’(providedthereisnoothervectorcalled‘a(chǎn)ge’inthemainworkspace).Thedetach