Hi:
Using the plyr package, we can get the result as follows:
> library(plyr)
> my.fun <- function(x, mult) mult*sum(x)
> dat <- data.frame(x = 1:4, grp = c("a","a","b","b"))
> ddply(dat, .(grp), summarize, max = max(x), myfun = my.fun(x, 10))
grp max myfun
1 a 2 30
2 b 4 70
HTH,
Dennis
On Tue, Jan 26, 2010 at 8:26 AM, RINNER Heinrich <
heinrich.rin...@tirol.gv.at> wrote:
> Dear R-users,
>
> I am working with R version 2.10.1.
>
> Say I have is a simple function like this:
>
> > my.fun <- function(x, mult) mult*sum(x)
>
> Now, I want to apply this function along with some other (say 'max') to a
> simple data.frame, like:
>
> > dat <- data.frame(x = 1:4, grp = c("a","a","b","b"))
>
> Ideally, the result would look something like this (if mult = 10):
> max my.fun
> a 2 30
> b 4 70
>
> I have tried it that way:
>
> apply.more.functions <- function(dat, FUN = c("max", "my.fun"), ...) {
> res <- NULL
> for(f in FUN) res[[f]] <- tapply(dat$x, dat$grp, FUN = f, ...)
> data.frame(res)
> }
>
> # let's test it:
> > apply.more.functions(dat, FUN = c("max", "min"))
> max min
> a 2 1
> b 4 3
> # perfect!
>
> # now, with an additional argument:
> > apply.more.functions(dat, FUN = c("max", "my.fun"), mult = 10)
> max my.fun
> a 10 30
> b 10 70
> # uhuh!
> Apparently, 'mult' has been used in the calculation of 'max' as well.
> How can I modify apply.more.functions in order to avoid this?
>
> Your advice would be appreciated;
> Kind regards
> Heinrich.
>
> ______________________________________________
> R-help@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.
>
[[alternative HTML version deleted]]
______________________________________________
R-help@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.
