Kotlin Map - isNotEmpty() Function

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The Kotlin Map isNotEmpty() function is used to return the boolean value. True if the map is not empty means the map contains elements. False if the map does not contains any element.

There are the following use cases of the isNotEmpty() function:

• Validation: It ensure that the map contains element before proceeding with operation that required non-empty map.
• Conditional Logic: Execute different action based on whether a collection is empty or not.
• User Notification: If the map is empty, it displays a message to users based on the availability of items, such as "No items found."

Syntax

Following is the syntax of Kotlin map isNotEmpty() function −

Map.isNotEmpty()

Parameters

This function does not accepts any parameters.

Return value

This function returns true if the map contains elements otherwise returns false.

Example 1: Checking Whether Map is Empty or not

Let's see a basic example of the isNotEmpty() function, which returns true if the map is not empty.

fun main(args: Array<String>) {
   val map = mapOf(1 to "aman", 2 to "akash", 3 to "Rahul");
   val isnotempty = map.isNotEmpty();
   if(isnotempty == true){
      println("map is not empty!")
      println(map)
   }else{
      println("map is empty!")
   }
}

Output

Following is the output −

map is not empty!
{1=aman, 2=akash, 3=Rahul}

Example 2: Short-Circuit Logic

The following example combines isNotEmpty() with the other checks to simplify the logic −

fun main(args: Array<String>) {
   val tasks = mapOf(1 to 'A', 5 to 'E', 10 to 'J')

   if (tasks.isNotEmpty()|| tasks.size>2) {
      println("map is not empty: " + tasks)
      println("Tasks are ready for processing.")
      println("${tasks.size}")
   } else {
      println("Not enough tasks to proceed.")
   }
}

Output

Following is the output −

map is not empty: {1=A, 5=E, 10=J}
Tasks are ready for processing.
3

Example 3: If the Map is Empty

This is another example of isNotEmpty() function if the map is empty, it return the false −

fun main(args: Array<String>) {
   val map = mapOf<Int, String>()   
   val res = map.isNotEmpty();
   println("Is map not empty? " + res)
}

Output

Following is the output −

Is map not empty? false