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

From: My Coyne <mcoyne_at_boninc.com>
Date: Tue, 15 Jan 2008 12:56:04 -0500

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.
>
>
>
> --My Coyne
>
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> [[alternative HTML version deleted]]
>
> ______________________________________________
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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

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