sign
Signum Function
Description
Extracts the sign of each element in a vector and returns a vector of numeric values of the same length as the input.
Usage
sign(x)
Arguments
| x | an atomic object. Missing values (NA) are allowed. | 
 
Details
Missing values in the argument(s) create missing values in the result. 
Value
For a numeric argument, returns 1, 0, and -1 corresponding to 
positive, zero, or negative values of the argument. For complex data, 
the result is equal to x/Mod(x) when x is not zero, and 
it is equal to 0+0i when it is zero. 
sign is not defined for character data. 
See Also
Examples
x <- c(-Inf, -3.14, 0, 3.14, Inf)
sign(x)
# [1] -1 -1  0  1  1
sign(x)*sqrt(abs(x)) # a signed square root