newbie's question about dataframe

Liaw, Andy wrote:

Something like this should do it:

 dat$Z <- with(dat, as.numeric(Y >= Y[order(Y, decreasing=TRUE)[10]]))

I was just about to post

   dat$Z <- as.numeric(rank(-dat$Y) <= 10)

so here it is, anyway. ;-)


Uwe

Andy

From: Wensui Liu

I have a dataframe containing X and Y. Right now, I want to create
another variable in the dataframe, named Z, such that for Z = 1 for
the top 10 largest value of Y and Z = 0 for the rest values of Y.

I really appreciate your help. Have a great weekend.