R help - Mar 2004 - how to delete a matrix column

Hello,
I am new to R, How to delete a matrix column.
Thanks,

You can use

dataset$columnname=NULL

HCD
 
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Harold C. Doran
Director of Research and Evaluation
New American Schools
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-----Original Message-----
From: Aimin Yan [mailto:aiminy at iastate.edu]
Sent: Tuesday, March 02, 2004 11:59 AM
To: r-help at stat.math.ethz.ch
Subject: [R] how to delete a matrix column


Hello,
I am new to R, How to delete a matrix column.
Thanks,

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

Shouldn't this be in the "An introduction to R", It is explained
for a
vector but I couldn't find it for matrix.

A<-matrix(1:25,5,5)
A<-A[,-2] # delete column 2
A<-A[,-c(1,4)] #delete columns 1 and 4


Angel


Aimin Yan wrote:
>Hello,
>I am new to R, How to delete a matrix column.
>Thanks,
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide! 
>http://www.R-project.org/posting-guide.html
>
>.
>

Aimin Yan wrote:
> I am new to R, How to delete a matrix column.
e.g. y <- x[,-5] deletes column 5

I was going to point out to the inquirer where this feature
is documented --- but I can't bleedin' find it!!!

Can anyone tell me?  I tried ?"[" but got no joy that
I could discern.

				cheers,

					Rolf Turner
					rolf at math.unb.ca

I would recommend here

y <- subset(x, select= -someColName)

which is not xref'd from ?"[" (though the obscure .subset is),
and is not mentioned in the relevant section of the 
Introduction to R either.

I once foolishly offered to amend this section of the manual,
but I have subsequently realised that I haven't the faintest idea
how to even start doing that.
> -----Original Message-----
> From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk]
> Sent: 02 March 2004 19:22
> To: Rolf Turner
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] how to delete a matrix column
> 
> 
> Security Warning: 
> If you are not sure an attachment is safe to open contact 
> Andy on x234. 
> There are 0 attachments with this message. 
> ________________________________________________________________ 
>  
> On Tue, 2 Mar 2004, Rolf Turner wrote:
> 
> > Aimin Yan wrote:
> > 
> > > I am new to R, How to delete a matrix column.
> > 
> > e.g. y <- x[,-5] deletes column 5
> > 
> > I was going to point out to the inquirer where this feature
> > is documented --- but I can't bleedin' find it!!!
> > 
> > Can anyone tell me?  I tried ?"[" but got no joy that
> > I could discern.
> 
> `An Introduction to R', for one.
> 
> The help page for "[" is long enough, but needs to be split/have
some
> xrefs added for things like this.
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
http://www.R-project.org/posting-guide.html  
 
Simon Fear 
Senior Statistician 
Syne qua non Ltd 
Tel: +44 (0) 1379 644449 
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