Don't fixate on avoiding loops. Bury them in a function so you don't have to see them and then you just want something that does the right thing quickly enough. (I'm assuming this is not a homework/puzzle type problem where you are not allowed to use loops). E.g., the following does the job (with no error checking): Ybar <- function(u, Y) { result <- Y[[1]](u) for(Yi in Y[-1]) result <- result + Yi(u) result/length(Y) } You could probably shoehorn this into a call to Reduce but there must be a for loop in Reduce.
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com ________________________________ From: Eduardo de Oliveira Horta [mailto:eduardo.oliveiraho...@gmail.com] Sent: Tuesday, November 16, 2010 4:15 PM To: David Winsemius Cc: Phil Spector; r-help@r-project.org; www...@gmail.com; William Dunlap Subject: Re: [R] Vectors out of lists? Thanks, guys... but it seems these suggestions won't work. Let me try to be more specific with a simple example: Y<-list() Y[[1]]<-function(u) sqrt(u) Y[[2]]<-function(u) sin(u) Y[[3]]<-function(u) 1/2*u I wanted something equivalent to Ybar<-function(u){ 1/3*(Y[[1]](u) + Y[[2]](u) + Y[[3]](u)) } but with arbitrary length(Y) and without using any loops. Also, I can't allow for discretization, since I must be able to evaluate Ybar at any u, as I'm going to integrate it with the function "integrate". Thanks again, Eduardo Horta [[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.