On Wed, 18 Jun 2014 04:24:58 PM yzh lin wrote:
> Hi, every R user,
>
> I wanna output names of objects, I googled codes from website,
but it
> was not what I wanted.
>
> the codes are as following:
>
> f <- function (...)
> {
> unevaluatedArgs <- substitute(...())
> evaluatedArgs <- list(...)
> stopifnot(length(unevaluatedArgs) == length(evaluatedArgs))
> tags <- vapply(unevaluatedArgs, FUN=function(x) deparse(x)[1],
> FUN.VALUE=character(1))
> if (!is.null(tmp <- names(evaluatedArgs))) {
> # if argument is tagged, tag=expr, use the tag
> i <- !is.na(tmp) & tmp != ""
> tags[i] <- tmp[i]
> }
> tags
> }
>
> f(a1=log(1:4), m1=1:4, c1=pi)
>
> results:
> > f(a1=log(1:4), m1=1:4, c1=pi)
>
> a1 m1 c1
> "a1" "m1" "c1"
>
>
> what I wanted is outputting "log(1:4) " "1:4", "pi" , while not "a1" "m1"
> "c1" .
>
> Coulde someone tell me how to get the results I wanted?
>
Hi Yuanzhen,
This may be of some help:
f<-function (...) {
unevaluatedArgs <- unlist(substitute(...()))
tags<-NA
for(arg in 1:length(unevaluatedArgs))
tags[arg]<-deparse(unevaluatedArgs[[arg]])
tags
}
f(a1=log(1:4), m1=1:4, c1=pi)
[1] "log(1:4)" "1:4" "pi"
Jim
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