Incidence Matrix of Levels within a Factor

Description

Incidence matrix of levels within a factor

Usage

at.level(x, level)

Arguments

Value

incidence matrix for level in x

Author(s)

Jarrod Hadfield j.hadfield@ed.ac.uk

See Also

at.set

Examples

fac<-gl(3,10,30, labels=letters[1:3])
x<-rnorm(30)
model.matrix(~at.level(fac,"b"):x)