[R] problem accessing complex list data frames

[Nick Sabbe]

Hello Germán.

You probably want something like:
sapply(vmat, function(curMat){
		curMat[,999] != 0
	})
Or if you want the indices, just surround this with a which.

HTH.

Nick Sabbe
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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Germán Sanchis
Sent: woensdag 8 december 2010 11:50
To: r-help at r-project.org
Subject: [R] problem accessing complex list data frames

Hi all.

I am currently attempting to build a list of sparse matrixes. That I have
already achieved, by

> vmat <- list()
> for (i in 1:n) {
>   vmat <- c(vmat, sparseMatrix(i,j,x=data) }

How I am trying to select those elements from the list where the column e.g.
999 is not null. I can do this for one of the sparse matrices with

> which(vmat[[1]][,999] != 0)

which returns the rows where such column is non-zero.

However, my purpose is to obtain the list indices of the sparse matrices
with such non-zero elements. I tried things like

which(vmat[[]][,999] != 0)
which(vmat[,,999] != 0)
sapply(vmat, which, [,999] != 0)

but none worked... any help will be appreciated!!

Cheers,

German

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