This question was just answered yesterday in this post: http://r.789695.n4.nabble.com/Correlations-by-subgroups-td3599548.html#a3600553
One solution: x<-c(1,1,1,1,1,2,2,2,2,2) y<-rnorm(10) z<-y+rnorm(10) by(data.frame(y,z),factor(x),cor) HTH, Daniel Mateus Rabello wrote: > > Hi, > How can I accomplish this in R. Example: > > I have the following data.frame: > > data <- > data.frame(x=c(1,2,3,4,5,6,5,3,7,1,0,4,8),y=c(1,2,1,2,2,2,1,1,1,2,2,2,2),z=c(5,8,4,3,4,1,6,3,3,6,3,5,7)) > > Supposing that data$y is a factor, I would like to find the Spearman > correlation between data$x and data$z indexing it by data$y. > To be more specific, I want to find two correlations: between x and z with > y==1 and the same correlation with x and z where y==2. > Something like: > > cor(data$x[data$y==1],data$z[data$y==1],method= "spearman") and > cor(data$x[data$y==2],data$z[data$y==2],method= "spearman"), > > but without having to write all the values for data$y and use cor more > than once. > > I hope I made myself clear. > Thanks > Mateus > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org 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. > -- View this message in context: http://r.789695.n4.nabble.com/Conditional-Correlation-tp3607080p3607134.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org 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.
