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.