none

Common
JVM
JS
Native
1.0
fun < T > Array < out T > . none ( ) : Boolean
(source)
fun ByteArray . none ( ) : Boolean
(source)
fun ShortArray . none ( ) : Boolean
(source)
fun IntArray . none ( ) : Boolean
(source)
fun LongArray . none ( ) : Boolean
(source)
fun FloatArray . none ( ) : Boolean
(source)
fun DoubleArray . none ( ) : Boolean
(source)
fun BooleanArray . none ( ) : Boolean
(source)
fun CharArray . none ( ) : Boolean
(source)
@ExperimentalUnsignedTypes fun UIntArray . none ( ) : Boolean
(source)
@ExperimentalUnsignedTypes fun ULongArray . none ( ) : Boolean
(source)
@ExperimentalUnsignedTypes fun UByteArray . none ( ) : Boolean
(source)
@ExperimentalUnsignedTypes fun UShortArray . none ( ) : Boolean
(source)

Returns true if the array has no elements.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val emptyList = emptyList<Int>()
println("emptyList.none() is ${emptyList.none()}") // true

val nonEmptyList = listOf("one", "two", "three")
println("nonEmptyList.none() is ${nonEmptyList.none()}") // false
//sampleEnd
}
Common
JVM
JS
Native
1.0
inline fun < T > Array < out T > . none (
predicate : ( T ) -> Boolean
) : Boolean

(source)
inline fun ByteArray . none (
predicate : ( Byte ) -> Boolean
) : Boolean

(source)
inline fun ShortArray . none (
predicate : ( Short ) -> Boolean
) : Boolean

(source)
inline fun IntArray . none (
predicate : ( Int ) -> Boolean
) : Boolean

(source)
inline fun LongArray . none (
predicate : ( Long ) -> Boolean
) : Boolean

(source)
inline fun FloatArray . none (
predicate : ( Float ) -> Boolean
) : Boolean

(source)
inline fun DoubleArray . none (
predicate : ( Double ) -> Boolean
) : Boolean

(source)
inline fun BooleanArray . none (
predicate : ( Boolean ) -> Boolean
) : Boolean

(source)
inline fun CharArray . none (
predicate : ( Char ) -> Boolean
) : Boolean

(source)
inline fun < T > Iterable < T > . none (
predicate : ( T ) -> Boolean
) : Boolean

(source)
@ExperimentalUnsignedTypes inline fun UIntArray . none (
predicate : ( UInt ) -> Boolean
) : Boolean

(source)
@ExperimentalUnsignedTypes inline fun ULongArray . none (
predicate : ( ULong ) -> Boolean
) : Boolean

(source)
@ExperimentalUnsignedTypes inline fun UByteArray . none (
predicate : ( UByte ) -> Boolean
) : Boolean

(source)
@ExperimentalUnsignedTypes inline fun UShortArray . none (
predicate : ( UShort ) -> Boolean
) : Boolean

(source)

Returns true if no elements match the given predicate .

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val isEven: (Int) -> Boolean = { it % 2 == 0 }
val zeroToTen = 0..10
println("zeroToTen.none { isEven(it) } is ${zeroToTen.none { isEven(it) }}") // false
println("zeroToTen.none(isEven) is ${zeroToTen.none(isEven)}") // false

val odds = zeroToTen.map { it * 2 + 1 }
println("odds.none { isEven(it) } is ${odds.none { isEven(it) }}") // true

val emptyList = emptyList<Int>()
println("emptyList.none { true } is ${emptyList.none { true }}") // true
//sampleEnd
}
Common
JVM
JS
Native
1.0
fun < T > Iterable < T > . none ( ) : Boolean
(source)

Returns true if the collection has no elements.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val emptyList = emptyList<Int>()
println("emptyList.none() is ${emptyList.none()}") // true

val nonEmptyList = listOf("one", "two", "three")
println("nonEmptyList.none() is ${nonEmptyList.none()}") // false
//sampleEnd
}
Common
JVM
JS
Native
1.0
fun < K , V > Map < out K , V > . none ( ) : Boolean
(source)

Returns true if the map has no entries.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val emptyList = emptyList<Int>()
println("emptyList.none() is ${emptyList.none()}") // true

val nonEmptyList = listOf("one", "two", "three")
println("nonEmptyList.none() is ${nonEmptyList.none()}") // false
//sampleEnd
}
Common
JVM
JS
Native
1.0
inline fun < K , V > Map < out K , V > . none (
predicate : ( Entry < K , V > ) -> Boolean
) : Boolean

(source)

Returns true if no entries match the given predicate .

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val isEven: (Int) -> Boolean = { it % 2 == 0 }
val zeroToTen = 0..10
println("zeroToTen.none { isEven(it) } is ${zeroToTen.none { isEven(it) }}") // false
println("zeroToTen.none(isEven) is ${zeroToTen.none(isEven)}") // false

val odds = zeroToTen.map { it * 2 + 1 }
println("odds.none { isEven(it) } is ${odds.none { isEven(it) }}") // true

val emptyList = emptyList<Int>()
println("emptyList.none { true } is ${emptyList.none { true }}") // true
//sampleEnd
}