Here's a simple example of the type of function I'm trying to write,
where the first argument is a list of functions:
myfun <- function(funlist, vec){
tmp <- lapply(funlist, function(x)do.call(x, args = list(vec)))
names(tmp) <- names(funlist)
tmp
}
> myfun(list("Summation" = sum, prod, "Absolute value" =
abs), c(1, 4, 6, 7))
$Summation
[1] 18
[[2]]
[1] 168
$`Absolute value`
[1] 1 4 6 7
What I would like is for the names of the result to be the same as the
names of funlist (as is the case in components 1 and 3 above), but if
some components of funlist are unnamed, I would like the default name
in the result to be the name of the actual function used. So in the
above example, I want the name of the second component to default to
'prod', since funlist[[2]] has no name.
But the problem is that I can't get the function names corresponding
to the unnamed elements of funlist by using the usual
deparse(substitute)) trick, since they're part of a list which is
treated as one big argument. So deparse(substitute(funlist)) just
gives me one big character string of all the functions, and I'm not
sure how I can use that to get just the functions that aren't named.
Any ideas?
Thanks,
Andrew
On 25/10/2007 5:38 PM, Andrew Smith wrote:> Here's a simple example of the type of function I'm trying to write, > where the first argument is a list of functions: > > myfun <- function(funlist, vec){ > tmp <- lapply(funlist, function(x)do.call(x, args = list(vec))) > names(tmp) <- names(funlist) > tmp > } > >> myfun(list("Summation" = sum, prod, "Absolute value" = abs), c(1, 4, 6, 7)) > $Summation > [1] 18 > > [[2]] > [1] 168 > > $`Absolute value` > [1] 1 4 6 7 > > > What I would like is for the names of the result to be the same as the > names of funlist (as is the case in components 1 and 3 above), but if > some components of funlist are unnamed, I would like the default name > in the result to be the name of the actual function used. So in the > above example, I want the name of the second component to default to > 'prod', since funlist[[2]] has no name. > > But the problem is that I can't get the function names corresponding > to the unnamed elements of funlist by using the usual > deparse(substitute)) trick, since they're part of a list which is > treated as one big argument. So deparse(substitute(funlist)) just > gives me one big character string of all the functions, and I'm not > sure how I can use that to get just the functions that aren't named. > Any ideas?I wouldn't do this, but you could use substitute to get the funlist argument to myfun. It will be an expression which would deparse to list("Summation" = sum, prod, "Absolute value" = abs), but you could probably futz around and decompose it into its component parts. But is this really worth it? Duncan Murdoch
Check out: http://tolstoy.newcastle.edu.au/R/e2/help/06/10/2242.html On 10/25/07, Andrew Smith <andrewsmith81 at gmail.com> wrote:> Here's a simple example of the type of function I'm trying to write, > where the first argument is a list of functions: > > myfun <- function(funlist, vec){ > tmp <- lapply(funlist, function(x)do.call(x, args = list(vec))) > names(tmp) <- names(funlist) > tmp > } > > > myfun(list("Summation" = sum, prod, "Absolute value" = abs), c(1, 4, 6, 7)) > $Summation > [1] 18 > > [[2]] > [1] 168 > > $`Absolute value` > [1] 1 4 6 7 > > > What I would like is for the names of the result to be the same as the > names of funlist (as is the case in components 1 and 3 above), but if > some components of funlist are unnamed, I would like the default name > in the result to be the name of the actual function used. So in the > above example, I want the name of the second component to default to > 'prod', since funlist[[2]] has no name. > > But the problem is that I can't get the function names corresponding > to the unnamed elements of funlist by using the usual > deparse(substitute)) trick, since they're part of a list which is > treated as one big argument. So deparse(substitute(funlist)) just > gives me one big character string of all the functions, and I'm not > sure how I can use that to get just the functions that aren't named. > Any ideas? > > Thanks, > Andrew > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
This is one way to implement the idea the other responses point at:> myfun <- function(funlist, vec){+ tmp <- lapply(funlist, function(x)do.call(x, args = list(vec))) + names(tmp)[names(tmp) == ""] <- + sapply(match.call()[[2]], deparse)[-1][names(tmp) == ""] + tmp + }>> > myfun(list("Summation" = sum, prod, "Absolute value" = abs), c(1, 4, 6,+ 7)) $Summation [1] 18 $prod [1] 168 $`Absolute value` [1] 1 4 6 7 Steven McKinney Statistician Molecular Oncology and Breast Cancer Program British Columbia Cancer Research Centre email: smckinney +at+ bccrc +dot+ ca tel: 604-675-8000 x7561 BCCRC Molecular Oncology 675 West 10th Ave, Floor 4 Vancouver B.C. V5Z 1L3 Canada -----Original Message----- From: r-help-bounces at r-project.org on behalf of Andrew Smith Sent: Thu 10/25/2007 2:38 PM To: r-help at stat.math.ethz.ch Subject: [R] Deparsing part of a list argument Here's a simple example of the type of function I'm trying to write, where the first argument is a list of functions: myfun <- function(funlist, vec){ tmp <- lapply(funlist, function(x)do.call(x, args = list(vec))) names(tmp) <- names(funlist) tmp }> myfun(list("Summation" = sum, prod, "Absolute value" = abs), c(1, 4, 6, 7))$Summation [1] 18 [[2]] [1] 168 $`Absolute value` [1] 1 4 6 7 What I would like is for the names of the result to be the same as the names of funlist (as is the case in components 1 and 3 above), but if some components of funlist are unnamed, I would like the default name in the result to be the name of the actual function used. So in the above example, I want the name of the second component to default to 'prod', since funlist[[2]] has no name. But the problem is that I can't get the function names corresponding to the unnamed elements of funlist by using the usual deparse(substitute)) trick, since they're part of a list which is treated as one big argument. So deparse(substitute(funlist)) just gives me one big character string of all the functions, and I'm not sure how I can use that to get just the functions that aren't named. Any ideas? Thanks, Andrew ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.