R help - Jul 2000 - filtering values

I was wondering if there is a simple way to filter out a bunch of
specific vales from a vector (eg zero).

Also, is there a way to create a null vector?  What I mean by this is
that if I declare a vector vector <- NA, it is a vector with [NA].  I
want an empty vector, so that I can append to it later.

Thanks

Alex

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On Wed, 5 Jul 2000, amorgan wrote:
> I was wondering if there is a simple way to filter out a bunch of
> specific vales from a vector (eg zero).
x[x!=42] removes all the 42s 
x[!is.na(x)] removes all the NAs

 
> Also, is there a way to create a null vector?  What I mean by this is
> that if I declare a vector vector <- NA, it is a vector with [NA].  I
> want an empty vector, so that I can append to it later.
numeric(0) is a vector of length 0. Remember that repeatedly appending is
slower than creating a vector and then putting things in it.

	-thomas

Thomas Lumley
Assistant Professor, Biostatistics
University of Washington, Seattle

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