create a vector looping over a frame
On Fri, 18 Jul 2003, Siddique, Amer wrote:
I have a data.frame
names(popA)
[1] "Year" "Series" "Age" "WM" "WF" "HM" "HF" "BM" [9] "BF" "IM" "IF" "AM" "AF" "Yr" how do i loop over a subset of variables in this frame to create a vector of length equal to the number of variables in the subset such that the vector's ith element is the result of an aggregate fncn applied to the ith variable? eg, sumvar<-c(sum(WM),...,sum(AF))
sumvar <- sapply(popA[ ,4:13], sum)
You can use any function, even a user-written one, in place of sum().
When you see the help for sapply(), remember that a data.frame is
also a list ("inherits" from list).
- tom blackwell - u michigan medical school - ann arbor -