[R] extraction from a list of vectors

Duncan Murdoch dmurdoch at pair.com
Mon Jun 18 03:50:40 CEST 2001

On Sun, 17 Jun 2001 17:10:26 -0500, you wrote:

>	Hi , 
>	I know this should be easy, but I haven't figured out a fast way to
>do it. 
>	I have a list of vectors: mylist <- list(vector1, vector2, ...,
>	(The vectors are made of integers. They vary in length from about 1
>to 10). 
>	I also have a vector of indices: myidx <- c( i1, i2, ..., iN). 
>	From these I'd like to make this: newvector <- c(vector1[i1],
>vector2[i2], ..., vectorN[iN]). 

I don't know if this is fast or not, but I think it gives the result
you want:

unlist(sapply(myidx,function(x) mylist[[x]]))

Duncan Murdoch

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