一个可能的解决方案是在函数中使用mget，直到返回列表，然后将xyz与带有c的列表合并。您需要将要添加的列指定为字符向量才能完成此工作：

getvar = function(...){
  return(d[,c(xyz = mean(hp),mget(...)),cyl])
}

getvar(c("mpg","cyl","disp"))

给出：

> getvar(c("mpg","disp"))
    cyl       xyz  mpg cyl  disp
 1:   6 122.28571 21.0   6 160.0
 2:   6 122.28571 21.0   6 160.0
 3:   6 122.28571 21.4   6 258.0
 4:   6 122.28571 18.1   6 225.0
 5:   6 122.28571 19.2   6 167.6
 6:   6 122.28571 17.8   6 167.6
 7:   6 122.28571 19.7   6 145.0
 8:   4  82.63636 22.8   4 108.0
 9:   4  82.63636 24.4   4 146.7
10:   4  82.63636 22.8   4 140.8
....

或者作为替代方案，@Rhonak's answer（@ zx8754的thx）略有变化：

getvar = function(...){
  mc <- match.call(expand.dots = FALSE)
  x <- as.character(mc$...)
  d[,mget(x)),cyl]
}

getvar(mpg,cyl,disp)

要在不引用列名的情况下使其工作，您必须使用一些非标准的评估策略：

getvar = function(...){
  vars <- substitute(list(xyz = mean(hp),...))
  return(d[,eval(vars),cyl])
}

getvar(mpg,disp)

    cyl       xyz  mpg cyl  disp
 1:   6 122.28571 21.0   6 160.0
 2:   6 122.28571 21.0   6 160.0
 3:   6 122.28571 21.4   6 258.0
 4:   6 122.28571 18.1   6 225.0
 5:   6 122.28571 19.2   6 167.6
...etc...

以@Konrad Rudolph here的答案为基础，我们可以编写函数

getvar = function(...){
   dots = match.call(expand.dots = FALSE)$...
   cols = sapply(dots,deparse)
   d[,mget(cols)),cyl]
   #thanks to @Jaap for simplified version
}

getvar(mpg,disp)
#    cyl    xyz  mpg cyl  disp
# 1:   6 122.29 21.0   6 160.0
# 2:   6 122.29 21.0   6 160.0
# 3:   6 122.29 21.4   6 258.0
# 4:   6 122.29 18.1   6 225.0
# 5:   6 122.29 19.2   6 167.6
# 6:   6 122.29 17.8   6 167.6
#....