The isNotEmpty method of List can be used to check if the List contains at least one element.
fun <T> Collection<T>.isNotEmpty(): Boolean
This method doesn’t take any argument.
This method returns true if the List contains at least one element. Otherwise, false will be returned.
The below code demonstrates how to use the isNotEmpty method in Kotlin:
fun main() {// create a empty List of integerval emptyList:List<Int> = listOf()println("emptyList : ${emptyList}")println("emptyList.isNotEmpty() : ${emptyList.isNotEmpty()}") // false//create another list with elementsval validList:List<Int> = listOf(1,2,3)println("\nvalidList : ${validList}")println("validList.isNotEmpty() : ${validList.isNotEmpty()}") // true}
In the above code:
Line 3: We create an emptyList using the listOf method.
Line 5: We use the isNotEmpty method to check if the emptyList contains at least one element. But the emptyList contains no elements, so false is returned.
Line 8: We create a list with the name validList using the listOf method. The validList has three elements, 1,2,3.
Line 10: We use the isNotEmpty method to check if the validList contains at least one element. The validList contains three elements, so true is returned.