On Jan 22, 2013, at 2:24 PM, Dominic Roye wrote:
Hello,
How i can use a costum function in tapply which has more than one variable?
I mean sum(x) only needs one object but what when i have a function
function(x,y) with more, how i indicate where are the other variables
to use?7
You can use:
lapply(split( multi_col_object, category_vec) , function(x,y){sum(x,y)} )
aggregate(dat, category, FUN=sum)
Or:
do.call(rbind, by( multi_col_object, category_vec, function(x,y){ } )
Sometimes `Reduce` is more compact. Other times `mapply` is needed.
--
David Winsemius
Alameda, CA, USA
__
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.