[R] array indexing and which
Werner Wernersen
pensterfuzzer at yahoo.de
Sun Apr 17 19:13:12 CEST 2005
Hi R friends!
I am stuck with a stupid question: I can circumvent it
but I would like to
understand why it is wrong. It would be nice if you
could give me a hint...
I have an 2D array d and do the following:
ids <- which(d[,1]>0)
then I have a vector gk with same column size as d and
do:
ids2 <- which(gk[ids]==1)
but I can't interprete the result I get in ids2.
I get the expected result when I use:
which(gk==1 & d[,1]>0)
Why is the first version wrong?
The reason why I try to use the ids vectors is that I
want to avoid recomputation.
Thanks for your help!
Werner
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