At 17:06 09/08/2009, Peng Yu wrote: >Hi, > >I know '.' is not a separator in R as in C++. I am wondering where it >discusses the detailed usage of '.' in R. Can somebody point me a >webpage, a manual or a book that discuss this? It has a special meaning in a formula. ?formula tells you more >Regards, >Peng Michael Dewey http://www.aghmed.fsnet.co.uk