How to Convert an Array of Key-Value Pairs to a Map in Kotlin

How to Convert an Array of Key-Value Pairs to a Map in Kotlin ?

Answer

To convert an array of key-value pairs to a map in Kotlin, you can use the `toMap` function, which creates a map from a collection of key-value pairs.

✐ Examples

1 Converting a List of Pairs to a Map

We can convert a list of key-value pairs to a map in Kotlin using the `toMap` function, which directly converts a list of pairs to a map.

For example,

We start by declaring and initializing a list of key-value pairs named pairs. In this example, the pairs are represented as pairs of two elements: a key and a value.
We convert the list of pairs to a map using the toMap function.
We print the resulting map to the console using the println function to verify the conversion.

Kotlin Program

val pairs = listOf(
    1 to 10,
    2 to 20,
    3 to 30,
    4 to 40,
    5 to 50
)

// Convert the list of pairs to a map
val myMap = pairs.toMap()

// Print the resulting map
println("Map from list of pairs:")
myMap.forEach { (key, value) ->
    println("$key: $value")
}

Output

Map from list of pairs:
1: 10
2: 20
3: 30
4: 40
5: 50

2 Converting an Array of Pairs to a Map

We can convert an array of key-value pairs to a map in Kotlin using the `toMap` function, which directly converts an array of pairs to a map.

For example,

We start by declaring and initializing an array of key-value pairs named pairs. In this example, the pairs are represented as pairs of two elements: a key and a value.
We convert the array of pairs to a map using the toMap function.
We print the resulting map to the console using the println function to verify the conversion.

Kotlin Program

val pairs = arrayOf(
    1 to 10,
    2 to 20,
    3 to 30,
    4 to 40,
    5 to 50
)

// Convert the array of pairs to a map
val myMap = pairs.toMap()

// Print the resulting map
println("Map from array of pairs:")
myMap.forEach { (key, value) ->
    println("$key: $value")
}

Output

Map from array of pairs:
1: 10
2: 20
3: 30
4: 40
5: 50

3 Converting a List of Objects to a Map

We can convert a list of objects with key and value properties to a map in Kotlin by using the `associateBy` function, which creates a map from the objects based on the key property.

For example,

We start by declaring and initializing a list of objects named pairs. In this example, each object has key and value properties.
We convert the list of objects to a map using the associateBy function, specifying the key and value properties.
We print the resulting map to the console using the println function to verify the conversion.

Kotlin Program

data class Pair(val key: Int, val value: Int)

val pairs = listOf(
    Pair(1, 10),
    Pair(2, 20),
    Pair(3, 30),
    Pair(4, 40),
    Pair(5, 50)
)

// Convert the list of objects to a map
val myMap = pairs.associateBy({ it.key }, { it.value })

// Print the resulting map
println("Map from list of objects:")
myMap.forEach { (key, value) ->
    println("$key: $value")
}

Output

Map from list of objects:
1: 10
2: 20
3: 30
4: 40
5: 50

Summary

In this tutorial, we learned How to Convert an Array of Key-Value Pairs to a Map in Kotlin language with well detailed examples.

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How to Convert an Array of Key-Value Pairs to a Map in Kotlin