containsKey
Returns true
if the map contains the specified key.
Since Kotlin
1.3Samples
import kotlin.test.*
import java.util.*
fun main() {
//sampleStart
val map = mapOf(1 to "one", 2 to "two")
println("map.containsKey(1) is ${map.containsKey(1)}") // true
println("map.containsKey(-1) is ${map.containsKey(-1)}") // false
//sampleEnd
}