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

aaa<-function(yvar,data) {
   bbb1 <- data.frame(ftable(xtabs(~ smk + alc + can,data=data)))
   print(bbb1)
   yvarc <- as.character(match.call()$yvar)
   subs<- bbb1[, yvarc]==1

   bbb2<-subset(bbb1,subs,select=c(1,2,4))
   print(bbb2)

}
aaa(yvar=smk,data=dat)

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

aaa<-function(yvar,data) {
   bbb1 <- data.frame(ftable(xtabs(~ smk + alc + can,data=data)))
   print(bbb1)
   subs <- eval(yval, bbb1)==1
   bbb2<-subset(bbb1,subs,select=c(1,2,4))
   print(bbb2)
}
aaa(yvar=can,data=dat)

输出的结果不对！