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

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