Math.factor
Math Group Method for Factor Objects
Description
Generates an error if a Math Group function is
called on a factor or ordered factor.
Usage
Math.factor(x, ...)
Arguments
| x |
any object that inherits from class "factor"
|
| ... |
not used in this method.
|
Details
This method is called whenever any of the Math Group functions is
called on a factor or ordered factor.
It generates an error "<function name> not meaningful for factors",
because all the Math Group functions require a numerical object as an argument.
This method exists in order to prevent the Math Group functions
from automatically converting factors or ordered factors to numeric objects.
Explicitly call as.integer on a factor
if you want to use the numeric representation of the
equivalence relation defined by the factor.
See Also
Examples
color <- c("pink", "red", "green", "red", "red", "blue")
colors <- factor(color, c("red", "green", "blue"))
sin(colors)
# Error in Math.factor(colors) : sin not meaningful for factors
as.integer(colors)
# [1] NA 1 2 1 1 3
sin(as.integer(colors))
# [1] NA 0.8414710 0.9092974 0.8414710 0.8414710 0.1411200