Determine if a value exists in a Kotlin Map

This article explores different ways to check if a value exists in a Map in Kotlin.

1. Using `containsValue()` function

The recommended solution to find a value in a Map is using the containsValue() function. It returns true if the map contains one or more keys corresponding to the specified value. If the value is a custom object, don’t forget to override the equals and hashCode method.

fun main() {

val map: MutableMap<Char, Int> = mutableMapOf()

for (i in 65..90) {

map[i.toChar()] = i

}

val value = 70

val exist = map.containsValue(value)

println(exist) // true

}

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2. Using `any()` function

Another plausible way involves getting the mutable collection of the values contained in the map and searching the specified value in it. Here’s a working example:

fun main() {

val map: MutableMap<Char, Int> = mutableMapOf()

for (i in 65..90) {

map[i.toChar()] = i

}

val value = 70

val exist = map.values.any { it == value }

println(exist) // true

}

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3. Using Loop

Finally, we can write custom logic to determine if a value exists in a Map. Here’s how the code would look like:

fun main() {

val map: MutableMap<Char, Int> = mutableMapOf()

for (i in 65..90) {

map[i.toChar()] = i

}

val value = 70

var exist = false

for (v in map.values) {

if (v == value) {

exist = true

break

}

println(exist) // true

}

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That’s all about checking if a value exists in a Map in Kotlin.

Determine if a value exists in a Kotlin Map

1. Using containsValue() function

2. Using any() function

3. Using Loop

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1. Using `containsValue()` function

2. Using `any()` function