R函数详解

> paste("Hello","world")
[1] "Hello world"

> paste("A", 1:6, sep = "")
[1] "A1" "A2" "A3" "A4" "A5" "A6"

> paste(letters[1:6],collapse=",")
[1] "a,b,c,d,e,f"

> paste("A", 1:6, sep = "", collapse=",")
[1] "A1,A2,A3,A4,A5,A6"

> paste(letters[1:4], seq=‘_‘)
[1] "a _" "b _" "c _" "d _"

> path <- ‘E:\\mytestdata\\‘
> setwd(path)
> dir.data <- dir(path)
> dir.data
[1] "a.csv" "b.csv" "c.csv" "d.csv"
>for(i in 1:length(dir.data)){
>data <- read.csv(paste(path,dir.data[i],sep=‘‘))
>}

write.csv(a.csv,file=paste(path,‘data.csv‘))

paste(‘select * from student where date =‘,‘date‘,sep=" ")

> date1 <- 20150101
> date2 <- 20151231
> paste0("select * from sales where stat_date between ",date1," and ",date2)
[1] "select * from sales where stat_date between 20150101 and 20151231"