R help - Jan 2008 - Newbie Question -- Remove entire column in a matrix

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.

 

Many thanks in advance.

 

--My Coyne

 

 


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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
>
>
>
> Many thanks in advance.
>
>
>
> --My Coyne
>
>
>
>
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>
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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