F# - Boolean Operators

The following table shows all the Boolean operators supported by F# language. Assume variable A holds true and variable B holds false, then −

Operator	Description	Example
&&	Called Boolean AND operator. If both the operands are non-zero, then condition becomes true.	(A && B) is false.
\|\|	Called Boolean OR Operator. If any of the two operands is non-zero, then condition becomes true.	(A \|\| B) is true.
not	Called Boolean NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.	not (A && B) is true.

Example

Live Demo

let mutable a : bool = true;
let mutable b : bool = true;

if ( a && b ) then
   printfn "Line 1 - Condition is true"
else
   printfn "Line 1 - Condition is not true"

if ( a || b ) then
   printfn "Line 2 - Condition is true"
else
   printfn "Line 2 - Condition is not true"

(* lets change the value of a *)

a <- false
if ( a && b ) then
   printfn "Line 3 - Condition is true"
else
   printfn "Line 3 - Condition is not true"

if ( a || b ) then
   printfn "Line 4 - Condition is true"
else
   printfn "Line 4 - Condition is not true"

When you compile and execute the program, it yields the following output −

Line 1 - Condition is true
Line 2 - Condition is true
Line 3 - Condition is not true
Line 4 - Condition is true

fsharp_operators.htm