sum a list of vectors
"Stoyanov, Tsvetan" <tsvetan.stoyanov at mirant.com> writes:
In Mathematica there is a neat feature, where you can change the
head of a list from "list" to say "+" and obtain a sum of the list
elements. I can't find a way to sum a list of vectors of same length
or list of matrices of the same dimension and was curious if
something like that exists in R. do.call("+",list) doesn't work
because "+" accepts only two arguments, I can obviously use loops
but this is quite slow and inelegant.
psum <- function(...)apply(cbind(...),1,sum) psum(1:3,4:6,1:9)
O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907