[R] setdiff for data.frames?

[Jason Rupert]

I have two data.frames.

One is the subset of the other.  I need to determine what rows were removed from the superset data.frame to form the subset data.frame. 

I was hoping to turn up functionality similar to setdiff for data.frames, but did not have any luck.   It seems I need to find a function that performs the oposite as "merge".


> dim(superset_dataframe)
[1] 248  31
> dim(subset_dataframe)
[1] 214  31

Thank you for any suggestions of functions that might exist that might help.