R: return first value that exceeds 0.8 within groups :     data<-data.frame(c(A,A,A,A,B,B,B,C,C,C),c(0.2,0.78,0.82,0,1,0.1,0.81,1,0.8,0.92,1))

Hello!

I would like to choose only first 80% within each group (A,B). Means I cannot use ordinary <. Any ideas?