R语言︱构造新序列

#数值构造rep与seq
rep(1:4,each=2)#依次重复1:4两遍
rep(1:4,2)  #注意，重复1:4两遍
seq(from=3,to=5,by=0.2)


rep(seq(from=3,to=5,by=0.2),2) #混合使用

> rep(c("id","use"),list(2,3))
[1] "id"  "id"  "use" "use" "use"
> rep(c("id","use"),each=2)
[1] "id"  "id"  "use" "use"
> rep(c("id","use"),2)
[1] "id"  "use" "id"  "use"
> rep(c("id","use"),unlist(2,3))
[1] "id"  "use" "id"  "use"

> rep(c("id","use"),list(2,3))
[1] "id"  "id"  "use" "use" "use"

#构造矩阵
matrix(1:15,nrow=3,ncol=5,byrow=T)  #byrow按行的顺序（横向）赋值；bycol按列（竖）赋值
array(1:15,dim=c(3,5)) #只能按列（竖）赋值

#字符构造paste


paste("CK", 1:6, sep="")      
paste("CK", 1:6, sep="*")         #对比


paste("CK", 1:6,collapse ="") 
paste("CK", 1:6,collapse = "_")   #对比
#seq代表是ck与数值1 之间用啥记号，如：ck_1,ck*2
#collapse代表是ck1与ck2之间用啥记号如：ck1_ck2   ck1 * ck2

#paste与list合用
x <- list(a="aaa", b="bbb", c="ccc") 
y <- list(d=1, e=2) 
z=paste(x, y, sep="-")
paste("T", z, sep=":") 
#list能够很好与paste函数应用起来

#3、利用List批量读出操作
#难点：如果构造输出表格的名称——paste来构造名称
flie=list()
xlsxflie=paste(1:2,".xlsx",sep="")

for(i in 1:2){
flie[[i]]=paste("C:/Users/long/Desktop/",xlsxflie[i],sep="")
write.xlsx(data.list2[[i]],file)
}