[R] finding dedicated indexes?

[Peter Wolf]

Thomas Bruns wrote:

> I've got a matrix of two columns, say:
> > d <- t(array(1:20,dim=c(2,10)))
> ...
> now I need those values from column #2 where column #1 is equal to
> certain values. eg.:
> > i <- c(13,5,19)
> The following doesn't work but you may get the idea:
> >print( d[ d[,1]==i ,2])

Hello Thomas, 
what about:

> d <- t(array(1:20,dim=c(2,10)))
> i <- c(13,5,19)
> d[match(i,d[,1]), 2]
[1] 14  6 20

Peter

------------------------------------------------------------
Dr. Peter Wolf			pwolf at wiwi.uni-bielefelde.de
Statistik/Informatik
Wirtschaftswissenschaften
Uni Bielefeld
Bielefeld 
Germany
------------------------------------------------------------


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