In Kotlin we have a huge list of such functions but here we will share some of the most used functions. last: return the last element of the list. Note this exclusive works where ‘nullableVariable’ is immutable (i.e. isEmpty: boolean value to check if the list is empty or not. It’s a pragmatic language with a very low learning curve, and can be quickly grasped by Java developers. size: Return the size of the list. In the above program, we've two strings str1 and str2. We've also created a function isNullOrEmpty() which checks, as the name suggests, whether the string is null or empty. 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. This example demonstrates how to Check if Android EditText is empty in Kotlin. indexOf: return the index position of a given value. Example: Input: str = "" Output: True Step 1 − Create a new project in Android Studio, go to File? ... and none. This means that behind-the-scenes, Kotlin translates the case element in to collection.contains(element). first: return the first element in the list. Given a string, we have to check whether it is an empty, blank or NULL string. Also, we need to make sure that we do one check before passing the index because for index = -1, it will throw ArrayIndexOutOfBoundsException. Nullable Collection If list is null, instead of returning null, you return an empty List, which still adheres to the ... You’ve just told Kotlin that the List can include nulls. It returns number of elements in a sequence. >>> 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. 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? To check if the argument is in a list: In the following example, we check if linkedlist of planets is empty or not and print a … In Python, empty list object evaluates to false. Check if LinkedList is empty We can check for emptiness of a LinkedList using isEmpty function. Hence following conditional statement can be used to check if list is empty. str1 is null or empty. New Project and fill all required details to create a new project. Step 2 − Add the following code to res/layout/activity_main.xml. That’s why you don’t need the extra null check. Submitted by IncludeHelp, on April 27, 2020 . Kotlin is 100% compatible with all existing Java frameworks, and has good tooling support. str2 is null or empty. For this reason, Kotlin provides the in operator, which is syntactic sugar for the contains() method. It requires one more step, list[index], to get the element from the list. 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. If the list doesn’t contain any element defined by the predicate, it will return -1. Covers the Kotlin List methods any, all, and none. 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. Here, you added safe call operators. str1 contains null value and str2 is an empty string. :] In fact, Kotlin takes null into account when you’re testing for equality in general. , we 've also created a function isNullOrEmpty ( ) which checks, as the name suggests, the! 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