baptiste auguie <ba208 <at> exeter.ac.uk> writes: > > I'm trying to use the reshape package to perform a merging operation > on a list of data.frames as illustrated below, > > > a <- 1:10 > > example <- list( data.frame(a=a, b=sin(a)), data.frame(a=a, > > b=cos(a)) ) > > > > melt(example, id = a) > > this produces the desired result, where the data.frames have been > coerced into one with a common identifier variable "a". However, it > seems that if "a" is of mode numeric it is not recognized as an id > variable, > > > a <- as.numeric(1:10) > > > > example <- list(data.frame(a=a, b=sin(a)), data.frame(a=a, b=cos(a))) > > > > melt(example, id = a) # this does not use a as an id variable >
This is the documented behavior: Only integers and factors are used for grouping, but as.numeric is double, even if 1:10 looks like integers a <- as.integer(1:10) or simply a <- 1:10 Dieter ______________________________________________ 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.
