Kotlin String - isNotEmpty() Function

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The Kotlin string isNotEmpty() function is used to check whether the string has a character sequence. If the string contains character sequence returns true; Otherwise returns false.

This function is commonly used in scenarios where we want to validate input, handle optional data, or avoid operations on empty strings.

Syntax

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

fun CharSequence.isNotEmpty(): Boolean

Parameters

This function does not accepts any parameters.

Return value

This function returns a Boolean value, which is true if the string is not empty; Otherwise false.

Example 1: Check If a String Empty or Not

Following is the basic example, here how we can use isNotEmpty() function with a string in kotlin −

fun main() {
   // non empty string
   val string = "tutorialspoint"
   val res = string.isNotEmpty()
   if(res == true){
      println("string is not empty")
   }
   else {
      println("string is empty")
   }
}

Output

Following is the output −

string is not empty

Example 2: Input Validation

Now, let's see another example. For input validation, we are using the isNotEmpty() function to check if a user has provided input in a form field before proceeding −

fun main() {
   val userInput = "Aman123"
   if (userInput.isNotEmpty()) {
      println("Your Input is not empty but it is wrong.")
   } else {
      println("Input field is empty")
   }
}

Output

If input field is filled with wrong details −

Your Input is not empty but it is wrong.

Example 3: If the String is Empty

In the following example, the isNotEmpty function returns false, if the string is empty −

fun main() {
   val userInput = ""
   val res = userInput.isNotEmpty()
   println("is string not empty?: ${res}")
}

Output

Following is the output −

is string not empty?: false