How to Clear All Key-Value Pairs from a Map in Kotlin

How to Clear All Key-Value Pairs from a Map in Kotlin ?

Answer

To clear all key-value pairs from a map in Kotlin, you can use the clear method. This method removes all elements from the map, leaving it empty.

✐ Examples

1 Clearing All Key-Value Pairs Using clear Method

We can clear all key-value pairs from a map in Kotlin using the clear method, which removes all elements from the map.

For example,

We start by declaring and initializing a mutable map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the clear method to remove all key-value pairs from the map.
We print the size of the map using the size property to verify that the map is empty.

Kotlin Program

fun main() {
    // Declare and initialize a mutable map
    val myMap: MutableMap<String, Int> = mutableMapOf(
        "one" to 1,
        "two" to 2,
        "three" to 3
    )

    // Clear all key-value pairs using clear method
    myMap.clear()

    // Print the size of the map
    println("Size of the map after clearing: ${myMap.size}")
}

Output

Size of the map after clearing: 0

2 Clearing an Already Empty Map

We can use the clear method on an already empty map in Kotlin, and it will still leave the map empty.

For example,

We start by declaring and initializing an empty mutable map named myMap. In this example, the map has string keys and integer values.
We use the clear method to remove all key-value pairs from the map, even though it is already empty.
We print the size of the map using the size property to verify that the map is still empty.

Kotlin Program

fun main() {
    // Declare and initialize an empty mutable map
    val myMap: MutableMap<String, Int> = mutableMapOf()

    // Clear the map using clear method
    myMap.clear()

    // Print the size of the map
    println("Size of the map after clearing: ${myMap.size}")
}

Output

Size of the map after clearing: 0

3 Clearing a Map After Inserting Elements

We can insert key-value pairs into a map and then clear all key-value pairs using the clear method.

For example,

We start by declaring and initializing a mutable map named myMap and inserting some key-value pairs into it. In this example, the map has string keys and integer values.
We use the clear method to remove all key-value pairs from the map.
We print the size of the map using the size property to verify that the map is empty.

Kotlin Program

fun main() {
    // Declare and initialize a mutable map
    val myMap: MutableMap<String, Int> = mutableMapOf()
    myMap["one"] = 1
    myMap["two"] = 2
    myMap["three"] = 3

    // Clear all key-value pairs using clear method
    myMap.clear()

    // Print the size of the map
    println("Size of the map after clearing: ${myMap.size}")
}

Output

Size of the map after clearing: 0

Summary

In this tutorial, we learned How to Clear All Key-Value Pairs from a Map in Kotlin language with well detailed examples.

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