[R] indexing without looping
Hello, 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:[EMAIL PROTECTED] __ R-help@stat.math.ethz.ch 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.
Re: [R] indexing without looping
One way would be to use merge, like this: merge(assignation,data.frame(class=x),all.y=TRUE) There might well be better ways... On 01/02/07, javier garcia-pintado [EMAIL PROTECTED] wrote: Hello, 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:[EMAIL PROTECTED] __ R-help@stat.math.ethz.ch 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. -- = David Barron Said Business School University of Oxford Park End Street Oxford OX1 1HP __ R-help@stat.math.ethz.ch 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.
Re: [R] indexing without looping
Hi, xt - assignation$value[match(x,assignation$class)] HTH ido __ R-help@stat.math.ethz.ch 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.
Re: [R] indexing without looping
javier garcia-pintado jgarcia at ija.csic.es writes: Hello, 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, you might try 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 x - c(1,1,2,7,6,5,4,3,2,2,2) x [1] 1 1 2 7 6 5 4 3 2 2 2 merge( x, assignation, by.x=1, by.y=2, all.x=T ) x value 1 1 6.5 2 1 6.5 3 2 12.0 4 2 12.0 5 2 12.0 6 2 12.0 7 3 7.5 8 4NA 9 5 8.5 10 6NA 11 7NA __ R-help@stat.math.ethz.ch 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.
