[R] How to search an element in matrix ?

Vadim Ogranovich vograno at evafunds.com
Mon Apr 11 06:51:35 CEST 2005


A matrix is a vector as well (it is stored by columns), so it has two
ways of indexing [i,j] and [i]. It may be easier for you to use the
latter, thus
which(x == 1) returns all indexes where the matrix x is equal to 1.

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of tong wang
> Sent: Sunday, April 10, 2005 9:37 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] How to search an element in matrix ?
> 
> Hi you guys,
>      I know this might be too simple a question to post, but 
> i searched a lot still couldn't find it.
>     Just want to find an element in matrix and return its 
> index , i think there should be some matrix version of 
> "match" which only works for vector to me.
>      thanks in advance for your help.
> 
> best,
> tong
> 
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