Sign

Returns the sign of number. Text-based programming languages typically call this function signum or sgn. The connector pane displays the default data types for this polymorphic function.

number can be a scalar number, array or cluster of numbers, array of clusters of numbers, and so on.
-1, 0, 1 returns 1 if the input value is greater than 0, returns 0 if the input value is equal to 0, and returns -1 if the input value is less than 0.