Logical Operators

 

A logical operator compares two operands or expressions and produces a true or false condition. There are two types of logical operators: conditional and Boolean. Conditional operators compare two values or expressions. Boolean operators connect string, numeric, or logical expressions together to determine true-false logic. Operators may be combined to create complex operators.

 

Conditional Operators

         =        Equal sign

                 <        Less than  

         >        Greater than

Boolean Operators

         NOT        Boolean (logical) NOT

                 ~        Tilde (logical NOT)

                 AND        Boolean AND

                 OR        Boolean OR

                 XOR        Boolean eXclusive OR

Combined operators                <>        Not equal

                 ~=        Not equal

                 NOT =        Not equal

                 <=        Less than or equal to

                 =<        Less than or equal to

                 ~>        Not greater than

                 NOT >        Not greater than

               >=        Greater than or equal to

                 =>        Greater than or equal to

                 ~<        Not less than

                 NOT <        Not less than

 

During logical evaluation, any non-zero numeric value or non-blank string value indicates a true condition, and a null (blank) string or zero numeric value indicates a false condition.

 

Example:

 

Logical Expression              Result

 

A = B                          True when A is equal to B

A < B                          True when A is less than B

A > B                          True when A is greater than B

A <> B, A ~= B, A NOT = B      True when A is not equal to B

A ~< B, A >= B, A NOT < B      True when A is not less than B

A ~> B, A <= B, A NOT > B      True when A is not greater than B

~ A, NOT A                     True when A is null or zero

A AND B                        True when A is true and B is true

 

A OR B                         True when A is true, or B is true, or both are true

A XOR B                        True when A is true or B is true, but not both.