Re: [R] list structure question

From: Gabor Grothendieck <ggrothendieck_at_myway.com>
Date: Fri 02 Jul 2004 - 01:59:40 EST

Here are three solutions but I think the original idea of just converting to a data frame and using rowMeans (last solution) is simplest:

L <- list(1:5, 6:10) # test list

do.call("mapply", c(sum,L)) / length(L)

sapply(seq(along=L),function(i)mean(sapply(L,"[[",i)))

rowMeans(as.data.frame(L))

Rajarshi Guha <rxg218 <at> psu.edu> writes:

:
: Hi,
: I have a list in which element is a vector (all of the same length and
: all numeric). I want to find the mean of the first elements of the
: vectors, the mean of the second elements of the vectors and so on.
:
: Currently I convert the list to a data.frame and apply rowMeans(). But
: is there a way to to do this directly on the list? I seem to recall a
: post in which there was such a function (or expression) but I just cant
: seem to find it.
:
: Could somebody point me in the right direction?



R-help@stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 02 02:03:28 2004

This archive was generated by hypermail 2.1.8 : Wed 03 Nov 2004 - 22:54:38 EST