I've defined the function
getFunNames <- function(FUN){
if (!is.list(FUN))
fun.names <- paste(deparse(substitute(FUN)), collapse = " ")
else
fun.names <- unlist(lapply(substitute(FUN)[-1], function(a) paste(a)))
fun.names
}
which gives what I want :> getFunNames(mean)
[1] "mean"> getFunNames(ff)
[1] "ff"> getFunNames(c(mean,ff))
[1] "mean" "ff"
If I call this within a function, things go wrong:
1] "FUN"> foo(ff)
[1] "FUN"> foo(c(mean,ff))
Error in substitute(FUN)[-1] : object is not subsettable
Obviously there are some things (quite a few things) which I have not
understood. Can anyone help?
Thanks
S?ren
On 10/5/2006 4:41 PM, S?ren H?jsgaard wrote:> I've defined the function > > getFunNames <- function(FUN){ > if (!is.list(FUN)) > fun.names <- paste(deparse(substitute(FUN)), collapse = " ") > else > fun.names <- unlist(lapply(substitute(FUN)[-1], function(a) paste(a))) > fun.names > } > > which gives what I want : >> getFunNames(mean) > [1] "mean" >> getFunNames(ff) > [1] "ff" >> getFunNames(c(mean,ff)) > [1] "mean" "ff" > > If I call this within a function, things go wrong: > 1] "FUN" >> foo(ff) > [1] "FUN" >> foo(c(mean,ff)) > Error in substitute(FUN)[-1] : object is not subsettable > > Obviously there are some things (quite a few things) which I have not understood. Can anyone help?I don't think you'll be able to do what you want. The problem is that R objects don't know their own name. "substitute" just gives you the unevaluated expression that was passed as an arg; so getFunNames is reporting on the expression in foo() that was used when it was called. You'll need to call substitute directly on the args to get the expressions, rather than passing them to another function to do that. In C code you have a bit more flexibility for non-standard evaluation, but not in R code. Duncan Murdoch
On Thu, 2006-10-05 at 22:41 +0200, S?ren H?jsgaard wrote:> I've defined the function > > getFunNames <- function(FUN){ > if (!is.list(FUN)) > fun.names <- paste(deparse(substitute(FUN)), collapse = " ") > else > fun.names <- unlist(lapply(substitute(FUN)[-1], function(a) paste(a))) > fun.names > }Hi, Try this:> getFunNames <- function(x)+ sapply(as.list(sys.call()[[2]][-1]),as.character)> getFunNames(c(mean,ff))[1] "mean" "ff"> foo <- function() getFunNames(c(mean,ff)) > foo()[1] "mean" "ff" HTH, Jerome -- Jerome Asselin, M.Sc., Agent de recherche, RHCE CHUM -- Centre de recherche 3875 rue St-Urbain, 3e etage // Montreal QC H2W 1V1 Tel.: 514-890-8000 Poste 15914; Fax: 514-412-7106
Probably the best you can hope for is to cover
most cases. This one uses match.call and handles
a number of cases and perhaps if you spend more time
on it might be able to add some cases where it fails
such as the second L below:
f <- function(x) {
if (!is.list(x)) x <- list(x)
if (is.null(names(x))) names(x) <- ""
names(x)[names(x) == ""] <- NA
mc <- match.call()[-1][[1]]
if (length(mc) > 1) mc <- mc[-1]
ifelse(is.na(names(x)), as.character(mc), names(x))
}
f(c(a = mean))
f(list(a = mean, b = sd))
f(c(f = function(x)x*x))
f(list(f = function(x)x*x, function(x)1-x))
L <- list(a = mean, b = sd)
f(L)
L <- list(a = mean, function(x)x)
f(L)
f(mean)
f(list(a = mean, sd))
f(list(mean, sd))
f(function(x)x*x)
f(list(function(x)x*x, function(y)y-1))
On 10/5/06, S?ren H?jsgaard <Soren.Hojsgaard at agrsci.dk>
wrote:> I've defined the function
>
> getFunNames <- function(FUN){
> if (!is.list(FUN))
> fun.names <- paste(deparse(substitute(FUN)), collapse = "
")
> else
> fun.names <- unlist(lapply(substitute(FUN)[-1], function(a)
paste(a)))
> fun.names
> }
>
> which gives what I want :
> > getFunNames(mean)
> [1] "mean"
> > getFunNames(ff)
> [1] "ff"
> > getFunNames(c(mean,ff))
> [1] "mean" "ff"
>
> If I call this within a function, things go wrong:
> 1] "FUN"
> > foo(ff)
> [1] "FUN"
> > foo(c(mean,ff))
> Error in substitute(FUN)[-1] : object is not subsettable
>
> Obviously there are some things (quite a few things) which I have not
understood. Can anyone help?
> Thanks
> S?ren
>
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