On 2020-04-09 18:00 +0000, aiguo li wrote: | That is awesome! Thanks. Dear AiGuo,
I thought: why make this overly complicated, when this is also possible: a <- matrix(LETTERS[1:16], nrow=4) X <- split(x=a[,-1], f=a[,1]) lapply(X=X, FUN=as.factor) Best, Rasmus ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.