The answer is the function setdiff(), but I suppose you have to know what the operation is called to find it.
> setdiff(a, b) [1] 1 5 11 You may find it illuminating to see how it is implemented. On Thu, 11 Nov 2004, Alexander Sokol wrote: > Hello, > > I have the following very simple problem: > > Say I have two vectors, > > a<-c(1,7,4,5,9,11) > b<-c(7,4,9) > > I would like to create a vector containing the elements in a which are not in > b. > > Obviously, this is possible by writing > > a[a!=b[1] & a!=b[2] & a!=b[3]] > > But I would like a solution which is applicable to the situation where the > number of elements in b is unknown. > > I have looked in the R manuals, the FAQ and the mailing lists, but have been > unable to find a solution. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
