If na.rm
is FALSE
an NA
value in any of the arguments will cause
a value of NA
to be returned, otherwise
NA
values are ignored. This is a generic function: methods can be defined for it
directly or via the Summary
group generic.
For this to work properly, the arguments ...
should be
unnamed, and dispatch is on the first argument.
Logical true values are regarded as one, false values as zero.
For historical reasons, NULL
is accepted and treated as if it
were numeric(0)
.