Returns a list of pairs of each two adjacent elements in this collection. to each element, its index in the original collection and current accumulator value that starts with initial value. Returns an array of UByte containing all of the elements of this collection. Even though it’s not possible to do pattern matching using when in Kotlin, as is the case with the corresponding structures in Scala and other JVM languages, the when block is versatile enough to make us totally forget about these features. Returns an array of Short containing all of the elements of this collection. You can have a look at the introduction to the Kotlin Language article on Baeldung to learn more about the language. We can use Kotlin’s is an operator to check if the argument is an instance of a specified type. Returns an array of Char containing all of the elements of this collection. Groups elements of the original collection by the key returned by the given keySelector function * Returns the single element, or throws an exception if the list is empty or has more than one element. Appends all elements that are not null to the given destination. Searches this list or its range for the provided element using the binary search algorithm. using the specified keySelector function to extract a key from each element. Please note that we would be talking about 2 types of return in kotlin in this article – 1. while second list contains elements for which predicate yielded false. In any case, the Kotlin compiler will assume that every possible argument value is covered by the when block and will complain in case it is not. among all values produced by selector function applied to each element in the collection or null if there are no elements. produced by the valueSelector function applied to each element. Returns a list containing successive accumulation values generated by applying operation from left to right In contrast, Kotlin allows us to use the when block with any built-in or user-defined type. Creates a Grouping source from a collection to be used later with one of group-and-fold operations Returns a list containing all elements of the original collection and then the given element. The list is expected to be sorted into ascending order according to the Comparable natural ordering of its elements, second list is built from the second values of each pair from this collection. ; MutableList inherites List and supports read/write access, you can add, update or remove items. Returns a list containing only the non-null results of applying the given transform function Kotlin List is an interface and generic collection of elements. Returns index of the first element matching the given predicate, or -1 if the list does not contain such element. Before Kotlin 1.4, however, only qualified break and continue were allowed in a when expression inside a loop: As shown above, the break and continue are qualified with the @LOOP expression. Returns the first element matching the given predicate. A generic ordered collection of elements. Returns a Map containing key-value pairs provided by transform function In this task, you change the score to a LiveData object in the ScoreViewModel and attach an observer to it. Populates and returns the destination mutable map with key-value pairs, Accumulates value starting with initial value and applying operation from right to left to each element in the original collection. This essentially means that no break statements are needed at the end of each case block. Performs the given action on each element. Returns first index of element, or -1 if the collection does not contain element. size: Return the size of the list. Searches this list or its range for the provided element using the binary search algorithm. Searches this list or its range for an element having the key returned by the specified selector function equal to the provided key value using the binary search algorithm. str2 is null or empty. Returns an array of Double containing all of the elements of this collection. This article explores different ways to convert an array to a list using Kotlin. Groups elements of the original collection by the key returned by the given keySelector function This tutorial introduces the when{} block in Kotlin language and demonstrates the various ways that it can be used. One of the many things that attracted me most was how you could avoid the so dreaded NullPointerException by properly handling optional types. Kotlin - from a list of Maps, to a map grouped by key, val list: List>> = listOf() val map = list . Accumulates value starting with the first element and applying operation from left to right Let’s create a when a block that omits the argument: In Java, the switch statement can only be used with primitives and their boxed types, enums, and the String class. Returns a Map containing the elements from the given collection indexed by the key The List interface inherits form Collection class. Returns an array of Long containing all of the elements of this collection. When you run the program, the output will be: str1 is null or empty. Returns the smallest value among all values produced by selector function List.isEmpty () function returns true if the collection is empty (contains no elements), false otherwise. Returns the last element, or null if the list is empty. and value is provided by the valueTransform function applied to elements of the given collection. to current accumulator value and each element with its index in the original collection. 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