sum(..., na.rm=TRUE) oddity
Duncan Murdoch wrote:
...Is there ever any reason to name the summands? I'd think it would be reasonable to generate an error, or at least a warning, in a case where any of the arguments to be summed are named. For example
In parsing functions with an ellipsis in the argument list, R appears to consume unnamed arguments until it finds a recognized argument name or encounters an unresolvable data conflict. This is pretty reasonable behavior.
sum <- function (..., na.rm = FALSE) {
if (!is.null(names(list(...))))
stop(paste('Named summands:',paste(names(list(...)),collapse='
')))
.Internal(sum(..., na.rm = na.rm))
}
gives this:
sum(1,1,rm.na=TRUE)
Error in sum(1, 1, rm.na = TRUE) : Named summands: rm.na
What seems to be happening here is that you have explicitly named the argument, then supplied an argument with an name that cannot be resolved. I think the "misspelled argument name" is irrelevant to your original question. Jim