[R] Newbie Question -- Remove entire column in a matrix

[Charles C. Berry]

On Tue, 15 Jan 2008, My Coyne wrote:

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> I'm ordering "The R Book" and hope to learn a lot more about R. In a
> meantime, I have a matrix of digits and I would like to look for a column
> that contains zeroes and remove the entire column from the matrix.  I can
> write a piece of R code to do that (and it works); however, I think the
> R-experts  have more tricks to do such a 'simple' thing.

Is one of these what you want?

 	new.mat <- mat[ , colSums( mat==0 ) == 0 ]

 	new.mat <- mat[ , colSums( mat==0 ) < nrow(mat) ]


HTH,

Chuck

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> Many thanks in advance.
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> --My Coyne
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Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901