search for: speciesgroups

I know this seems like a very easy question (and maye it is) but I've been trying to simulate nested data and been unsucessful so far.. I want to simulate a varying number of species within a group; and then create an array to store the results of my for-loop. For example: groups<-3 species$groups<-as.integer(runif(groups,1,10)) #species per functional group ###create arrays to store