indexing
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 Garc?a-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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