Given something like ...
x <- c(3,2,4,3,5,4,3,2,4,5)
y <- c("A","B","B","A","A","A","A","B","A","B")
xy <- data.frame(x,y)
xy$w <- ifelse(xy$y=="A",xy$w[,x]*10,xy$w[,x]*15 )
want to see
x y w
1 3 A 30
2 2 B 30
3 4 B 60
4 3 A 30
5 5 A 50
6 4 A 40
7 3 A 30
8 2 B 30
9 4 A 40
10 5 B 75
but I get NA's
Jeff