Example: Input: str = "" Output: True str2 is null or empty. Kotlin | Check for empty string: Here, we are going to learn how to check whether a given string is an empty, blank or NULL string in Kotlin programming language? Given a string, we have to check whether it is an empty, blank or NULL string. indexOf: return the index position of a given value. In the above program, we've two strings str1 and str2. Check if LinkedList is empty We can check for emptiness of a LinkedList using isEmpty function. str1 is null or empty. This example demonstrates how to Check if Android EditText is empty in Kotlin. a local property which can’t be altered between the check and the utilization or a member ‘val’ which has a backing field and is not overridable), else it may happen that ‘nullableVariable’ changes to null after the check. >>> a=[] # Empty lists evaluate to False >>> if not a: print ("list is empty") else: print ("list is not empty") You can also use len() function. isEmpty: boolean value to check if the list is empty or not. Nullable Collection New Project and fill all required details to create a new project. We've also created a function isNullOrEmpty() which checks, as the name suggests, whether the string is null or empty. It’s a pragmatic language with a very low learning curve, and can be quickly grasped by Java developers. str1 contains null value and str2 is an empty string. Covers the Kotlin List methods any, all, and none. To check if the argument is in a list: Submitted by IncludeHelp, on April 27, 2020 . :] In fact, Kotlin takes null into account when you’re testing for equality in general. last: return the last element of the list. Hence following conditional statement can be used to check if list is empty. That’s why you don’t need the extra null check. Kotlin is 100% compatible with all existing Java frameworks, and has good tooling support. For this reason, Kotlin provides the in operator, which is syntactic sugar for the contains() method. If the list doesn’t contain any element defined by the predicate, it will return -1. In the following example, we check if linkedlist of planets is empty or not and print a … ... and none. Note this exclusive works where ‘nullableVariable’ is immutable (i.e. This means that behind-the-scenes, Kotlin translates the case element in to collection.contains(element). Here, you added safe call operators. first: return the first element in the list. Also, we need to make sure that we do one check before passing the index because for index = -1, it will throw ArrayIndexOutOfBoundsException. It returns number of elements in a sequence. Kotlin code might be compiled not only to JVM bytecode but to JavaScript and Native code as well, but this course is focused on Kotlin/JVM. size: Return the size of the list. In Kotlin we have a huge list of such functions but here we will share some of the most used functions. In Python, empty list object evaluates to false. Step 2 − Add the following code to res/layout/activity_main.xml. Step 1 − Create a new project in Android Studio, go to File? Here is how you can declare a Collection of Nullable Types in Kotlin - val listOfNullableTypes: List = listOf(1, 2, null, 3) // Works To filter non-null values from a list of nullable types, you can use the filterNotNull() function - val notNullList: List = listOfNullableTypes.filterNotNull() 2. 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