Random

Returns a repeatable random number generator seeded with the given seedInt value.

Two generators with the same seed produce the same sequence of values within the same version of Kotlin runtime.

Note: Future versions of Kotlin may change the algorithm of this seeded number generator so that it will return a sequence of values different from the current one for a given seed.

On JVM the returned generator is NOT thread-safe. Do not invoke it from multiple threads without proper synchronization.

Since Kotlin

1.3

Samples

import samples.*
import kotlin.math.sin
import kotlin.random.Random
import kotlin.test.assertTrue
fun main() { 
   //sampleStart 
   fun getRandomList(random: Random): List<Int> =
    List(10) { random.nextInt(0, 100) }

val randomValues1 = getRandomList(Random(42))
// prints the same sequence every time
assertPrints(randomValues1, "[33, 40, 41, 2, 41, 32, 21, 40, 69, 87]")

val randomValues2 = getRandomList(Random(42))
// random with the same seed produce the same sequence
assertTrue(randomValues1 == randomValues2)

val randomValues3 = getRandomList(Random(0))
// random with another seed produce another sequence
assertPrints(randomValues3, "[14, 48, 57, 67, 82, 7, 61, 27, 14, 59]") 
   //sampleEnd
}

fun Random(seed: Long): Random

Returns a repeatable random number generator seeded with the given seedLong value.

Two generators with the same seed produce the same sequence of values within the same version of Kotlin runtime.

Note: Future versions of Kotlin may change the algorithm of this seeded number generator so that it will return a sequence of values different from the current one for a given seed.

On JVM the returned generator is NOT thread-safe. Do not invoke it from multiple threads without proper synchronization.

Since Kotlin

1.3

Samples

import samples.*
import kotlin.math.sin
import kotlin.random.Random
import kotlin.test.assertTrue
fun main() { 
   //sampleStart 
   fun getRandomList(random: Random): List<Int> =
    List(10) { random.nextInt(0, 100) }

val randomValues1 = getRandomList(Random(42))
// prints the same sequence every time
assertPrints(randomValues1, "[33, 40, 41, 2, 41, 32, 21, 40, 69, 87]")

val randomValues2 = getRandomList(Random(42))
// random with the same seed produce the same sequence
assertTrue(randomValues1 == randomValues2)

val randomValues3 = getRandomList(Random(0))
// random with another seed produce another sequence
assertPrints(randomValues3, "[14, 48, 57, 67, 82, 7, 61, 27, 14, 59]") 
   //sampleEnd
}