[R] Convert a list to matrix

[jim holtman]

This should do what you want:

> m <- list()
> m[["A"]] <- 1
> m[["B"]] <- 2:3
> # get the maximum length
> maxLen <- max(sapply(m, length))
> # create a new list with elements padded out with NAs
> newM <- lapply(m, function(.ele){
+     c(.ele, rep(NA, maxLen))[1:maxLen]
+ })
> do.call(rbind, newM)
  [,1] [,2]
A    1   NA
B    2    3
>


On Sat, Feb 21, 2009 at 10:17 PM, Daren Tan <darentan76 at gmail.com> wrote:
> I would like to convert a list to matrix. This can be easily achieved via
> do.call. The only problem is each element of the list has different length,
> which causes the recycling of values. How can I have NA instead of recycled
> values ?
>
> m <- list()
> m[["A"]] <- 1
> m[["B"]] <- 2:3
> do.call(rbind, m)
>  [,1] [,2]
> A    1    1
> B    2    3
>
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>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?