[R] Extending each element in a list, or rbind()-ing arrays of different length without recycling

Stavros Macrakis macrakis at alum.mit.edu
Fri Feb 13 18:58:03 CET 2009


(typos corrected)

Combining the various approaches on the list, here's a simple
one-liner that puts the NAs at the end:

    t(apply(mat,1,function(r) { dr<-duplicated(r); c( r[!dr],
rep(NA,sum(dr)) ) }))

If you don't care where the NAs are, the following is a tad shorter
and perhaps clearer:

    mat[ t(apply(mat,1,duplicated)) ] <- NA                  # modifies mat

        -s

On Fri, Feb 13, 2009 at 12:49 PM, Stavros Macrakis
<macrakis at alum.mit.edu> wrote:
> Combining the various approaches on the list, here's a simple
> one-liner that puts the NAs at the end:
>
>     t(apply(mat,1,function(r) { dr<-duplicated(r); c( r[!dr],
> rep(NA,sum(dr)) ) ))
>
> If you don't care where the NAs are, the following is a tad shorter
> and perhaps clearer:
>
>     mat[ t(apply(mat,1,duplicated)) ] < -NA                  # modifies mat
>
>         -s
>




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