Booleans

The type Boolean represents boolean objects that can have two values: true and false. Boolean has a nullable counterpart declared as Boolean?.

Built-in operations on booleans include:

|| – disjunction (logical OR)
&& – conjunction (logical AND)
! – negation (logical NOT)

For example:

fun main() {
//sampleStart
    val myTrue: Boolean = true
    val myFalse: Boolean = false
    val boolNull: Boolean? = null

    println(myTrue || myFalse)
    // true
    println(myTrue && myFalse)
    // false
    println(!myTrue)
    // false
    println(boolNull)
    // null
//sampleEnd
}

The || and && operators work lazily, which means:

If the first operand is true, the || operator does not evaluate the second operand.
If the first operand is false, the && operator does not evaluate the second operand.

Last modified: 10 February 2025