Message-ID: <1BDB01B13696D411BD6200D0B7C854EA22F9D9@chi-prd-mail1.xcaliber.com>
Date: 2001-06-17T22:10:26Z
From: Jeff Miller
Subject: extraction from a list of vectors
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, ...,
vectorN).
(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]).
It's easy to do this using a for loop, but I need something that
will be fast for lists
with lengths of about 100,000. I've thought about using lapply, but
don't see how I can use it with "myidx".
Thanks in advance,
Jeff Miller
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