untb (version 1.7-7)

+.count: Add two count objects

Description

Adds two count objects

Usage

# S3 method for count
+(a,b)
# S3 method for census
+(a,b)

Arguments

a,b

objects of class count

Author

Robin K. S. Hankin, based on an R-help tip from Gabor Grothendiek

Details

Consider count objects a and b. Then a+b is a count object that records the number of each species in a and b combined. It is as though the organisms in the surveys were pooled.

Census objects are coerced to count objects, added, then the result coerced to a count object.

The operation is commutative and associative.

One might think that the addition method should use the frab package, but this would not account for extinct species.

Examples

a <- count(c(dogs=4,pigs=0,slugs=5))
b <- count(c(slugs=4,hogs=1,frogs=19))

a+b