4D Doc Center : Logical Operators

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4D v14.3

Logical Operators

4D supports two logical operators that work on Boolean expressions: conjunction (AND) and inclusive disjunction (OR). A logical AND returns TRUE if both expressions are TRUE. A logical OR returns TRUE if at least one of the expressions is TRUE.

4D also provides the Boolean functions True, False, and Not. For more information, see the descriptions of these commands.

The following table shows the logical operators:

Operation	Syntax	Returns	Expression	Value
AND	Boolean & Boolean	Boolean	("A" = "A") & (15 # 3)	True
			("A" = "B") & (15 # 3)	False
			("A" = "B") & (15 = 3)	False
OR	Boolean \| Boolean	Boolean	("A" = "A") \| (15 # 3)	True
			("A" = "B") \| (15 # 3)	True
			("A" = "B") \| (15 = 3)	False

The following is the truth table for the AND logical operator:

Expr1	Expr2	Expr1 & Expr2
True	True	True
True	False	False
False	True	False
False	False	False

The following is the truth table for the OR logical operator:

Expr1	Expr2	Expr1 \| Expr2
True	True	True
True	False	True
False	True	True
False	False	False

Tip: If you need to calculate the exclusive disjunction between Expr1 and Expr2, evaluate:

(Expr1|Expr2) & Not(Expr1 & Expr2)