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



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,

  1. 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.
  2. We use the clear method to remove all key-value pairs from the map.
  3. 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,

  1. We start by declaring and initializing an empty mutable map named myMap. In this example, the map has string keys and integer values.
  2. We use the clear method to remove all key-value pairs from the map, even though it is already empty.
  3. 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,

  1. 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.
  2. We use the clear method to remove all key-value pairs from the map.
  3. 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.




More Kotlin Maps Tutorials

  1. How to create an Empty Map in Kotlin ?
  2. How to create a Map with Initial Key-Value Pairs in Kotlin ?
  3. How to Print a Map in Kotlin ?
  4. How to Add a Key-Value Pair to a Map in Kotlin ?
  5. How to Set a Default Value for a Key in a Map in Kotlin ?
  6. How to Update the Value for a Key in a Map in Kotlin ?
  7. How to Check if a Map is Empty in Kotlin ?
  8. How to Check if a Key Exists in a Map in Kotlin ?
  9. How to Check if a Value Exists in a Map in Kotlin ?
  10. How to Get the Value Associated with a Key in a Map in Kotlin ?
  11. How to Remove a Key-Value Pair from a Map in Kotlin ?
  12. How to Remove Key-Value Pairs from a Map Based on Values in Kotlin ?
  13. How to Clear All Key-Value Pairs from a Map in Kotlin ?
  14. How to Iterate Over Keys in a Map in Kotlin ?
  15. How to Iterate Over Values in a Map in Kotlin ?
  16. How to Iterate Over Entries (Key-Value Pairs) in a Map in Kotlin ?
  17. How to Get the Size (Number of Key-Value Pairs) of a Map in Kotlin ?
  18. How to Convert a Map to an Array of Keys in Kotlin ?
  19. How to Convert a Map to an Array of Values in Kotlin ?
  20. How to Convert a Map to an Array of Key-Value Pairs in Kotlin ?
  21. How to Merge Two Maps in Kotlin ?
  22. How to Copy a Map in Kotlin ?
  23. How to Check if Two Maps are Equal in Kotlin ?
  24. How to Sort a Map by Keys in Kotlin ?
  25. How to Sort a Map by Values in Kotlin ?
  26. How to Filter a Map Based on Keys in Kotlin ?
  27. How to Filter a Map Based on Values in Kotlin ?
  28. How to Reduce Values in a Map to a Single Value in Kotlin ?
  29. How to Convert an Array of Key-Value Pairs to a Map in Kotlin ?
  30. How to Convert a Map to a JSON String in Kotlin ?
  31. How to Convert a JSON String to a Map in Kotlin ?
  32. How to Swap Keys and Values in a Map in Kotlin ?
  33. How to Create a Map of Maps in Kotlin ?
  34. How to Iterate Over a Map of Maps in Kotlin ?