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.
sign(x)a numeric vector
This is an internal generic primitive function: methods
can be defined for it directly or via the
Math group generic.
# NOT RUN {
sign(pi) # == 1
sign(-2:3) # -1 -1 0 1 1 1
# }