[R] indexing

[Dimitris Rizopoulos]

one way is the following:

assignation$value[match(x, assignation$class)]


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "javier garcia-pintado" <jgarcia at ija.csic.es>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, February 01, 2007 12:05 PM
Subject: [R] indexing


> Hello,
> In a nutshell, I've got a data.frame like this:
>
>> assignation <- 
>> data.frame(value=c(6.5,7.5,8.5,12.0),class=c(1,3,5,2))
>> assignation
>  value class
> 1   6.5     1
> 2   7.5     3
> 3   8.5     5
> 4  12.0     2
>>
>
> and a long vector of classes like this:
>
>> x <- c(1,1,2,7,6,5,4,3,2,2,2...)
>
> And would like to obtain  a vector of length = length(x), with the
> corresponding values extracted from assignation table. Like this:
>> x.value
> [1]  6.5  6.5 12.0   NA   NA  8.5   NA  7.5 12.0 12.0 12.0
>
> Could you help me with an elegant way to do this ?
> (I just can do it with looping for each class in the assignation 
> table,
> what a think is not perfect in R's sense)
>
> Wishes,
> Javier
> -- 
>
> Javier García-Pintado
> Institute of Earth Sciences Jaume Almera (CSIC)
> Lluis Sole Sabaris s/n, 08028 Barcelona
> Phone: +34 934095410
> Fax:   +34 934110012
> e-mail:jgarcia at ija.csic.es
>
>


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