+.count {untb}

Add two count objects

Description

Adds two count objects

Usage

## S3 method for class 'count'
a + b
## S3 method for class 'census'
a + b

Arguments

a, b

objects of class count

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.

Author(s)

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

Examples

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

a+b