Another approach would be > Y <- list(sqrt, sin, function(u) u/2) > Ybar <- function(u) rowMeans(sapply(Y, function(fun) fun(u))) > > integrate(Ybar, 0, 1) 0.4587882 with absolute error < 5.6e-05 >
i.e. make the function vectorized directly. Note, however, that if you had Y[[4]] <- function(u) 1 you would need to be careful and use something like Y[[4]] <- function(u) rep(1, length(u)) or indeed Y[[4]] <- Vectorize(function(u) 1) for the process to work. Bill Venables. -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Phil Spector Sent: Wednesday, 17 November 2010 10:24 AM To: Eduardo de Oliveira Horta Cc: r-help@r-project.org Subject: Re: [R] Vectors out of lists? Eduardo - Thanks for the reproducible example! > Y<-list() > Y[[1]]<-function(u) sqrt(u) > Y[[2]]<-function(u) sin(u) > Y[[3]]<-function(u) 1/2*u > Ybar = function(u)mean(sapply(Y,function(fun)fun(u))) Since integrate requires a function which accepts a vector and returns a vector, we'd need to use Vectorize() before trying to integrate: > integrate(Vectorize(Ybar),0,1) 0.4587882 with absolute error < 5.6e-05 - Phil Spector Statistical Computing Facility Department of Statistics UC Berkeley spec...@stat.berkeley.edu On Tue, 16 Nov 2010, Eduardo de Oliveira Horta wrote: > 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 > > ______________________________________________ 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.
