Re: [R] (no subject)

From: Johannes Huesing <>
Date: Tue, 18 Nov 2008 22:55:27 +0100

Salas, Andria Kay <> [Tue, Nov 18, 2008 at 04:10:06PM CET]:
> I need help with another problem I am having that deals with the generation of vectors that I asked about yesterday. I now need to have each value in the vector (all values either 1 or -1) have a probability p that it will switch signs (so, say, each value has a 50% chance of switching from -1 to 1 or visa versa). What would be the best way to go about doing this? Thank-you!!

Say you have a vector v, you can generate another vector randomly by

w <- sample(c(-1, 1), length(v), replace=TRUE)

and multiply v with w.

Johannes Hüsing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture  from such a trifling investment of fact.                (Mark Twain, "Life on the Mississippi")

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Received on Tue 18 Nov 2008 - 21:59:07 GMT

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