如何得到数据框

can <- c(rep(1, times = 231), rep(0, times = 178), rep(1, times = 11),rep(0, times = 38))
smk <- c(rep(1, times = 225), rep(0, times = 6), rep(1, times = 166),
         rep(0, times = 12), rep(1, times = 8), rep(0, times = 3), rep(1, times = 18),
         rep(0, times = 20))
alc <- c(rep(1, times = 409), rep(0, times = 49))
smk1 <- c(rep(1, times = 225), rep(0, times = 6), rep(1, times = 166),
          rep(0, times = 12), rep(1, times = 8), rep(0, times = 3), rep(1, times = 18),
          rep(0, times = 20))
alc1 <- c(rep(1, times = 409), rep(0, times = 49))


dat <- as.data.frame(cbind(alc, alc1,smk,smk1, can))




通过自己写的函数得到新的数据框
aaa<-function(yvar,xvars,data) {


}
如果调用aaa(yvar=can,xvar="smk alc",data=dat)
则得到新的数据框，其变量依次为为can smk alc


如果调用aaa(yvar=can,xvar="alc1 alc",data=dat)
则得到新的数据框，其变量依次为为can alc1 alc

谢谢！

aaa <- function(yvar, xvar, data) {
        yname <- deparse(match.call()$yvar)
        xvars <- unlist(strsplit(xvar, " "))
        data[, c(yname, xvars)]
}

xvars<-"smk alc"
如何把xvars变为"smk","alc"

1. aaa<-function(yvar = can, xvars = "smk alc", data = dat) {
   
2.   if (xvars == "smk alc") {
   
3.     data1 <- data.frame(data1.can = data$can,
   
4.                         data1.smk = data$smk,
   
5.                         data1.alc = data$alc)
   
6.     return(data1)
   
7.   } else {
   
8.     data2 <- data.frame(data2.can = data$can,
   
9.                         data2.alc1 = data$alc1,
   
10.                         data2.alc = data$alc)
    
11.     return(data2)
    
12.   }
    
13. }
    
14. aaa(yvar = can, xvars = "smk alc", data = dat)

复制代码

1. xvars = "smk alc"
   
2. xvar1 <- substr(xvars, 1, 3)
   
3. xvar2 <- substr(xvars, 5, 7)

复制代码

谢谢!不通用.

通用的就是楼上的了，牛