prod returns the product of all the values
present in its arguments.
prod(…, na.rm = FALSE)
numeric or complex or logical vectors.
logical. Should missing values be removed?
The product, a numeric (of type "double") or complex vector of length one.
NB: the product of an empty set is one, by definition.
This is part of the S4 Summary
group generic. Methods for it must use the signature
x, …, na.rm.
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
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole.