Not

Syntax:
NOT a

NOT is logical negation operator. It returns non-zero (truth) value if its argument is zero (false).
Operator NOT can be used with any types, including integer and float numeric types, String, Object and any user types. For numeric types NOT holds if the argument contains zero value in the respective format, for String type NOT holds if the argument does not contain any string or is undefined. For Object and user types NOT holds if the respective argument does not point at any valid object instance.