kotlin-stdlib/kotlin.collections/LinkedHashMap/put

put

expect open override fun put(key: K, value: V): V?(source)

Associates the specified value with the specified key in the map.

Since Kotlin

1.0

Return

the previous value associated with the key, or null if the key was not present in the map.

Samples

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

fun main() { 
   //sampleStart 
   val map = mutableMapOf(1 to "one", 2 to "two")
map[1] = "*ONE*"
println(map) // {1=*ONE*, 2=two}

map[3] = "tree"
println(map) // {1=*ONE*, 2=two, 3=tree}

println(map.put(3, "three")) // tree
println(map.put(4, "four")) // null 
   //sampleEnd
}