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

[My Coyne]

Really Cool.  THANK YOU

Both works,  only that New.mat is t is being transposed.   So, I added a
minor change:

New.mat <- matrix (mat [,colSums(mat==0) == 0], byrow = TRUE)






-----Original Message-----
From: Charles C. Berry [mailto:cberry at tajo.ucsd.edu] 
Sent: Tuesday, January 15, 2008 12:34 PM
To: My Coyne
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] Newbie Question -- Remove entire column in a matrix

On Tue, 15 Jan 2008, My Coyne wrote:

>
>
> 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
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