[R] subsetting a list of matrices

[Henrique Dallazuanna]

Try this:

subset(as.data.frame(do.call(rbind, lapply(l, "[", , 1))), row3 == "Message 1")

On Tue, Aug 23, 2011 at 1:28 PM, Lara Poplarski <larapoplarski at gmail.com> wrote:
> Hi all,
>
> I have an object that looks (roughly) like the following:
>
> l <- list(a = matrix(rnorm(9), 3), b = matrix(rnorm(9), 3), c =
> matrix(rnorm(9), 3))
>
> l$a[3,] <- sample(c("Message 1", "Message 2", "Message 3"))
> l$b[3,] <- sample(c("Message 1", "Message 2", "Message 3"))
> l$c[3,] <- sample(c("Message 1", "Message 2", "Message 3"))
>
> rownames(l$a) <- rownames(c(1:3), do.NULL = FALSE, prefix = "row")
> rownames(l$b) <- rownames(c(1:3), do.NULL = FALSE, prefix = "row")
> rownames(l$c) <- rownames(c(1:3), do.NULL = FALSE, prefix = "row")
>
> colnames(l$a) <- c("V1", "V2", "V3")
> colnames(l$b) <- c("V1", "V2", "V3")
> colnames(l$c) <- c("V1", "V2", "V3")
>
> I want to extract values (row1, V1) for the three sublists a, b, c,
> but only for those cases in which row3 == "Message 1". Could someone
> suggest how to proceed?
>
> Many thanks in advance,
> Lara
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O