Convert a "by" object to a data frame in R
- by lorin
I'm using the "by" function in R to chop up a data frame and apply a function to different parts, like this:
pairwise.compare <- function(x) {
Nright <- ...
Nwrong <- ...
Ntied <- ...
return(c(Nright=Nright, Nwrong=Nwrong, Ntied=Ntied))
}
Z.by <- by(rankings, INDICES=list(rankings$Rater, rankings$Class), FUN=pairwise.compare)
The result (Z.by) looks something like this:
: 4
: 357
Nright Nwrong Ntied
3 0 0
------------------------------------------------------------
: 8
: 357
NULL
------------------------------------------------------------
: 10
: 470
Nright Nwrong Ntied
3 4 1
------------------------------------------------------------
: 11
: 470
Nright Nwrong Ntied
12 4 1
What I would like is to have this result converted into a data frame (with the NULL entries not present) so it looks like this:
Rater Class Nright Nwrong Ntied
1 4 357 3 0 0
2 10 470 3 4 1
3 11 470 12 4 1
How do I do that?
