[R] array indexing and which

From: Werner Wernersen <pensterfuzzer_at_yahoo.de>
Date: Mon 18 Apr 2005 - 03:13:12 EST

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!


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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Apr 18 03:18:26 2005

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