How to Check if Two Maps are Equal in Kotlin

How to Check if Two Maps are Equal in Kotlin ?

Answer

To check if two maps are equal in Kotlin, you can use the == operator, which compares the key-value pairs of both maps. This method provides a straightforward way to determine if two maps contain the same elements.


✐ Examples

1 Checking Equality of Two Maps Using the == Operator

We can check if two maps are equal in Kotlin by using the == operator, which compares their key-value pairs.

For example,

  1. We start by declaring and initializing two maps named map1 and map2 with some key-value pairs. In this example, the maps have string keys and integer values.
  2. We use an if statement to compare map1 and map2 using the == operator.
  3. We print the result to the console using the println function to indicate whether the maps are equal or not.

Kotlin Program

fun main() {
    // Declare and initialize two maps
    val map1 = mapOf("one" to 1, "two" to 2, "three" to 3)
    val map2 = mapOf("one" to 1, "two" to 2, "three" to 3)

    // Check if the maps are equal
    if (map1 == map2) {
        println("Maps are equal")
    } else {
        println("Maps are not equal")
    }
}

Output

Maps are equal

2 Checking Equality of Two Maps with Different Sizes

We can also check if two maps with different sizes are equal in Kotlin by comparing their sizes first and then using the == operator to compare their key-value pairs.

For example,

  1. We start by declaring and initializing two maps named map1 and map2 with some key-value pairs. In this example, the maps have string keys and integer values, and they have different sizes.
  2. We use an if statement to compare the sizes of map1 and map2. If their sizes are not equal, we print a message indicating that the maps are not equal.
  3. If their sizes are equal, we use the == operator to compare the key-value pairs of both maps.
  4. We print the result to the console using the println function to indicate whether the maps are equal or not.

Kotlin Program

fun main() {
    // Declare and initialize two maps
    val map1 = mapOf("one" to 1, "two" to 2, "three" to 3)
    val map2 = mapOf("one" to 1, "two" to 2)

    // Check if the maps are equal
    if (map1.size != map2.size) {
        println("Maps are not equal")
    } else if (map1 == map2) {
        println("Maps are equal")
    } else {
        println("Maps are not equal")
    }
}

Output

Maps are not equal

3 Checking Equality of Two Maps Using a Helper Function

We can create a helper function to check if two maps are equal in Kotlin, which provides a reusable way to compare maps.

For example,

  1. We start by declaring and initializing two maps named map1 and map2 with some key-value pairs. In this example, the maps have string keys and integer values.
  2. We define a helper function named areMapsEqual that takes two maps as parameters and returns a boolean value indicating whether the maps are equal.
  3. Inside the helper function, we compare the sizes of the maps. If their sizes are not equal, we return false.
  4. If their sizes are equal, we use the == operator to compare the key-value pairs of both maps and return the result.
  5. We call the helper function with map1 and map2 as arguments and print the result to the console using the println function to indicate whether the maps are equal or not.

Kotlin Program

fun main() {
    // Declare and initialize two maps
    val map1 = mapOf("one" to 1, "two" to 2, "three" to 3)
    val map2 = mapOf("one" to 1, "two" to 2, "three" to 3)

    // Helper function to check if two maps are equal
    fun areMapsEqual(map1: Map<String, Int>, map2: Map<String, Int>): Boolean {
        if (map1.size != map2.size) {
            return false
        }
        return map1 == map2
    }

    // Check if the maps are equal using the helper function
    if (areMapsEqual(map1, map2)) {
        println("Maps are equal")
    } else {
        println("Maps are not equal")
    }
}

Output

Maps are equal

Summary

In this tutorial, we learned How to Check if Two Maps are Equal in Kotlin language with well detailed examples.


More Kotlin Maps Tutorials

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  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 ?
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