containsValue所在位置是kotlin.collections.containsValue，其相关用法介绍如下。

用法:

fun <K, V> Map<K, V>.containsValue(value: V): Boolean

如果映射将一个或多个键映射到指定的 value ，则返回 true 。

允许克服需要传递类型为 V 的值的 containsValue 的 type-safety 限制。

例子：

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

fun main(args: Array<String>) {
//sampleStart
val map: Map<String, Int> = mapOf("x" to 1, "y" to 2)

// member containsValue is used
println("map.containsValue(1) is ${map.containsValue(1)}") // true

// extension containsValue is used when the argument type is a supertype of the map value type
println("map.containsValue(1 as Number) is ${map.containsValue(1 as Number)}") // true
println("map.containsValue(2 as Any) is ${map.containsValue(2 as Any)}") // true

println("map.containsValue(\"string\" as Any) is ${map.containsValue("string" as Any)}") // false

// map.containsValue("string") // cannot call extension when the argument type and the map value type are unrelated at all
//sampleEnd
}

输出：

map.containsValue(1) is true
map.containsValue(1 as Number) is true
map.containsValue(2 as Any) is true
map.containsValue("string" as Any) is false