kotlin-stdlib/kotlin.collections/AbstractMutableMap/size

size

expect open override val size: Int(source)

Returns the number of key/value pairs in the map.

If a map contains more than Int.MAX_VALUE elements, the value of this property is unspecified. For implementations allowing to have more than Int.MAX_VALUE elements, it is recommended to explicitly document behavior of this property.

Since Kotlin

1.3

Samples

import kotlin.test.*
import java.util.*

fun main() { 
   //sampleStart 
   assertEquals(0, emptyMap<Int, Int>().size)

val mutableMap = mutableMapOf(1 to "one", 2 to "two")
assertEquals(2, mutableMap.size)

mutableMap[3] = "three"
assertEquals(3, mutableMap.size) 
   //sampleEnd
}