Re: [R] Count of unique factors within another factor

gt; > HTH, > Dennis > > On Sun, Jun 13, 2010 at 9:07 AM, Birdnerd <[hidden > email]<http://user/SendEmail.jtp?type=node&node=2253845&i=0>> > wrote: > > > > > I have a data frame with two factors (sampling 'unit', 'species'). I

[R] Count of unique factors within another factor

I have a data frame with two factors (sampling 'unit', 'species'). I want to calculate the number of unique 'species' per 'unit.' I can calculate the number of unique values for each variable separately, but can't get a count for each ‘unit’. > data=read.csv("C:/Desktop/sr_sort_practice.csv") > a