Here is an example using the builtin data set, CO2, where we aggregate uptake over Treatment for Plant equal to "Qn1" and Type equal to "Quebec".
with(subset(CO2, subset = Plant == "Qn1" & Type == "Quebec"), aggregate(list(uptake = uptake), list(Treatment = Treatment), sum)) or equivalently: with(CO2[CO2$Plant == "Qn1" & CO2$Type == "Quebec",], aggregate(list(uptake = uptake), list(Treatment = Treatment), sum)) or CO2a <- CO2[CO2$Plant == "Qn1" & CO2$Type == "Quebec",] aggregate(CO2a[,"uptake", drop=FALSE], CO2a[,"Treatment", drop=FALSE], sum) On 3/14/06, Antonio Olinto <[EMAIL PROTECTED]> wrote: > Hello all, > > I have a data frame with year, month, species, fishing gear and catch > (Y, M, S, F, C) and I want the sum of C by Y for species "A" and fishing > gear "trawl". > > I tried things like aggregate(C[S=="A" & F=="trawl"], list (Year = > Y[S=="A" & F=="trawl"]), fun=sum), but it didn't worked. > > To overcome this problem I did a subset as a new data frame and then I > used aggregate. But I'm sure there's a way to apply a filter in data frame. > > Thanks for any help. Best regards. > > Antonio Olinto > > ______________________________________________ > [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 > ______________________________________________ [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
