R help - Sep 2009 - Subsetting matrix with values from vector

Hello,

I have a large matrix (data), in which there is a column offerid. The values
are numbers (lets say 1:5)
There is another vector (idnew), which contains some of the offerids and
many more (3:10).

I want a subset of the matrix wiith only those rows, which match the
criteria of the vector.

How can I make it work?

Thanks!
-- 
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have a look at ?"%in%"


Best,
Dimitris


jorgusch wrote:
> Hello,
> 
> I have a large matrix (data), in which there is a column offerid. The
values
> are numbers (lets say 1:5)
> There is another vector (idnew), which contains some of the offerids and
> many more (3:10).
> 
> I want a subset of the matrix wiith only those rows, which match the
> criteria of the vector.
> 
> How can I make it work?
> 
> Thanks!
-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014

Hi jorgusch,

First, do not call your data, "data"  :-)

require(fortunes)
fortune('dog')

Here are two suggestions to do what you asked for:

# your data
id <- 1:5
idnew <- 3:10

# to get the indexes
id %in% idnew

# to get the id's matching the new vector
id[ id %in% idnew ]

# another way
intersect(id, idnew)

See ?"%in%" and ?intersect for more information.

HTH,
Jorge

On 9/15/09, jorgusch <hackl.schorsch at web.de>
wrote:
>
> Hello,
>
> I have a large matrix (data), in which there is a column offerid. The
values
> are numbers (lets say 1:5)
> There is another vector (idnew), which contains some of the offerids and
> many more (3:10).
>
> I want a subset of the matrix wiith only those rows, which match the
> criteria of the vector.
>
> How can I make it work?
>
> Thanks!
> --
> View this message in context:
>
http://www.nabble.com/Subsetting-matrix-with-values-from-vector-tp25450905p25450905.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
HTH,
Jorge Ivan VELEZ, NHGRI USA