sign returns a vector with the signs of the corresponding
elements of x (the sign of a real number is 1, 0, or $-1$
if the number is positive, zero, or negative, respectively).
Note that sign does not operate on complex vectors.
Usage
sign(x)
Arguments
x
a numeric vector
Details
This is an internal genericprimitive function: methods
can be defined for it directly or via the
Math group generic.