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

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

Answer

To convert a map to an array of key-value pairs in Kotlin, you can use the entries property to get a set of map entries and then convert this set to a list. This provides a convenient way to extract all key-value pairs from the map.

✐ Examples

1 Converting a Map to an Array of Key-Value Pairs Using entries Property

We can convert a map to an array of key-value pairs in Kotlin using the entries property, which provides a set of all entries in the map. We can then convert this set to a list.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the entries property to get a set of the key-value pairs in the map.
We convert the set of key-value pairs to a list using the toList method.
We store the list of key-value pairs in a variable named entriesList.
We print the key-value pairs to the console using a for loop and the println function to verify the conversion.

Kotlin Program

fun main() {
    // Declare and initialize a map
    val myMap = mapOf(
        "one" to 1,
        "two" to 2,
        "three" to 3
    )

    // Convert map to an array of key-value pairs
    val entriesList = myMap.entries.toList()

    // Print the key-value pairs
    println("Key-Value Pairs:")
    for (entry in entriesList) {
        println("${entry.key} to ${entry.value}")
    }
}

Output

Key-Value Pairs:
one to 1
two to 2
three to 3

2 Converting an Empty Map to an Array of Key-Value Pairs

We can also convert an empty map to an array of key-value pairs in Kotlin using the entries property, which returns an empty list when the map is empty.

For example,

We start by declaring an empty map named emptyMap with string keys and integer values.
We use the entries property to get a set of the key-value pairs in the empty map.
We convert the set of key-value pairs to a list using the toList method.
We store the list of key-value pairs in a variable named emptyEntriesList.
We print the key-value pairs to the console using the println function to verify that the list is empty.

Kotlin Program

fun main() {
    // Declare an empty map
    val emptyMap = mapOf<String, Int>()

    // Convert empty map to an array of key-value pairs
    val emptyEntriesList = emptyMap.entries.toList()

    // Print the key-value pairs
    println("Key-Value Pairs: $emptyEntriesList")
}

Output

Key-Value Pairs: []

3 Converting a Map to an Array of Key-Value Pairs After Adding Elements

We can convert a map to an array of key-value pairs in Kotlin after adding elements using the entries property, which provides an updated set of all key-value pairs in the map.

For example,

We start by declaring an empty mutable map named dynamicMap with string keys and integer values.
We add some key-value pairs to the map using the map's index notation.
We use the entries property to get a set of the key-value pairs in the map after adding elements.
We convert the set of key-value pairs to a list using the toList method.
We store the list of key-value pairs in a variable named dynamicEntriesList.
We print the key-value pairs to the console using a for loop and the println function to verify the updated list of key-value pairs.

Kotlin Program

fun main() {
    // Declare an empty mutable map
    val dynamicMap = mutableMapOf<String, Int>()

    // Add elements to the map
    dynamicMap["one"] = 1
    dynamicMap["two"] = 2
    dynamicMap["three"] = 3

    // Convert map to an array of key-value pairs after adding elements
    val dynamicEntriesList = dynamicMap.entries.toList()

    // Print the key-value pairs
    println("Key-Value Pairs:")
    for (entry in dynamicEntriesList) {
        println("${entry.key} to ${entry.value}")
    }
}

Output

Key-Value Pairs:
one to 1
two to 2
three to 3

Summary

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

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