Dear R-users, 

I am wondering why "^" operator alone returns a matrix, when operated on a data.frame (as opposed to all other arithmetic operators). Here's an example:

DF <- data.frame(x=1:5, y=6:10)
class(DF*DF) # [1] data.frame
class(DF^2) # [1] matrix

I posted here on SO: http://stackoverflow.com/questions/19964897/why-does-on-a-data-frame-return-a-matrix-instead-of-a-data-frame-like-do and got a very nice answer - it happens because a matrix is returned (obvious by looking at `Ops.data.frame`). However, what I'd like to understand is, *why* a matrix is returned for "^" alone? Here's an excerpt from Ops.data.frame (Thanks to Neal Fultz):

if (.Generic %in% c("+", "-", "*", "/", "%%", "%/%")) {
    names(value) <- cn
    data.frame(value, row.names = rn, check.names = FALSE, 
        check.rows = FALSE)
}
else matrix(unlist(value, recursive = FALSE, use.names = FALSE), 
    nrow = nr, dimnames = list(rn, cn))


It's clear that a matrix will be returned unless `.Generic` is one of those arithmetic operators. My question therefore is, is there any particular reason why "^" operator is being missed in the if-statement here? I can't think of a reason where this would break. Also ?`^` doesn't seem to mention anything about this coercion.

Please let me know if I should be posting this to R-devel list instead.

Thank you very much,
Arun


	[[alternative HTML version deleted]]

