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