On 2009-May-25 , at 15:34 , Jim Burke wrote: > Everyone's suggestions work. There are lots > of roads to solutions in R. This is wonderful! There's even more. In the package Hmisc, there is a %nin% command that does what you want. It is less standard (requires an additional package) but more syntactically pleasing. JiHO --- http://jo.irisson.free.fr/