Hi, > I'd like know how to sort a data frame in R for example how I should > do to sort by Catholic with swiss data frame like below It's in the FAQ : http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-can-I-sort-the-rows-of-a-data-frame_003f HTH, Julien -- Julien Barnier Groupe de recherche sur la socialisation ENS-LSH - Lyon, France