Hi Christian, It works better now. Thanks a lot. Julie At 09:32 08/07/2004 +0200, you wrote: >Hi Julie, > >as I understand your question you only want indices for exact matches to >"b". This can be achieved using regular expressions (see ?regex) > >nom <- c("a","b","ab") >grep("^b$",nom) > >I hope this helps? > >Christian