You can also use the sqldf package: > x unit species 1 123 ACMA 2 123 LIDE 3 123 LIDE 4 123 SESE 5 123 SESE 6 123 SESE 7 345 HEAR 8 345 LOHI 9 345 QUAG 10 345 TODI > require(sqldf) > sqldf('select unit, count(distinct species) as count from x group by unit') unit count 1 123 3 2 345 4 >
On Sun, Jun 13, 2010 at 12:07 PM, Birdnerd <haaszool...@gmail.com> wrote: > > 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") >> attach(data) > >> data[1:10,] > unit species > 1 123 ACMA > 2 123 LIDE > 3 123 LIDE > 4 123 SESE > 5 123 SESE > 6 123 SESE > 7 345 HEAR > 8 345 LOHI > 9 345 QUAG > 10 345 TODI….. > >> sr.unique<- lapply (data, unique) > $unit > [1] 123 345 216 > $species > [1] ACMA LIDE SESE HEAR LOHI QUAG TODI UMCA ARSP LIDE > >> sapply (sr.unique,length) > unit species > 3 10 > > Then, I get stuck here because this unique species count is not given for > each ‘unit’. > What I'd like to get is: > > unit species > 123 3 > 345 4 > 216 -- > > Thanks-- > > -- > View this message in context: > http://r.789695.n4.nabble.com/Count-of-unique-factors-within-another-factor-tp2253545p2253545.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.