R语言中的重要数据结构
1.向量  x<-c(1,2,3)
2.字符串  y<-"abc"  mode(y)
字符串操作函数：u<-paste("abc","de") v<-strsplit(u," ")
3.矩阵 m<-rbind(c(1,4),c(2,2)) m[1,2] m[1,]
《R语言实战》m<-matrix(1:20,nrow=5,ncol=4)
cells<-c(1,26,24,68) rnames<-c("R1","R2")
cnames<-c("C1","C2")
mymatrix<-matrix(cells,nrow=2,ncol=2,byrow=T,dimnames=list(rnames,cnames)) mymatrix
mymatrix<-matrix(cells,nrow=2,ncol=2,byrow=F,dimnames=list(rnames,cnames))mymatrix
4.列表 x<-list(u=2,v="abc") hn<-hist(Nile) str(hn) hnprint(hn)
5.数据框d<-data.frame(list(kids=c("jack","jill"),ages=c(12,10))) dd$ages
《R语言实战》patientid<-c(1,2,3,4) age<-c(22,24,35,35)
  diabetes<-c("type1","type2","type3","type4")
status<-c("poor","improved","excellent","poor")
patientdata<-data.frame(patientid,age,diabetes,status)
6.类？
7.拓展案例
getwd() setwd()
grade<-read.table("grade.txt",header=FALSE)
head(grade)
lma<-lm(grade[,2]~grade[,1])
attributes(lma)
lma$coef
lma
summary(lma)
lmb<-lm(grade[,2]~grade[,1]+grade[,3])