To perform all of the operations listed above on maps, you first need to get an entrySet of a map. Stream().collect(toMap(keyMapper, valueMapper)) Stream().noneMatch(), stream().anyMatch(), stream().allMatch()īuild maps from collection elements and certain values associated with them Stream().collect(oupingBy(classifier, counting()))Ĭheck whether collection elements satisfy a condition Group elements by a classifier and count them El forEachIndexed () genera los elementos del índice y sus valores. Es una función en línea que acepta una matriz como entrada.

Podemos usar la función forEachIndexed () para recuperar el índice actual. Get flat access to nested collection elementsĬollectionOfCollections.forEach(flatCollection::addAll) or collectionOfCollections.stream().flatMap().collect()Īpply the given function to every elementĪpply the provided operation to collection elements sequentially and return the accumulated result Obtenga el índice actual de un elemento en un bucle forEach usando forEachIndexed () en Kotlin. Operations on lists, sets, queues, and deques In Kotlin, there are many operations on collections that look exactly the same as their counterparts in Java. Operations that are the same in Java and Kotlin The second part of the guide, starting from Mutability, explains some of the differences by looking at specific cases.įor an introduction to collections, see the Collections overview or watch this video by Sebastian Aigner, Kotlin Developer Advocate.Īll of the examples below use Java and Kotlin standard library APIs only. It is divided into operations that are the same and operations that exist only in Kotlin. The first part of this guide contains a quick glossary of operations on the same collections in Java and Kotlin. It returns the index of an element which will be returned by a subsequent call to the next () function. Using ListIterator A simple solution is to use the nextIndex () function from the iterator returned by the ListIterator. It will help you migrate from Java to Kotlin and write your code in the authentically Kotlin way. Traverse a List with index in Kotlin This article explores different ways to traverse a list with the index in Kotlin. This guide explains and compares collection concepts and operations in Java and Kotlin. Hi I am using a for loop to call a coroutine method (that calls retrofit) and for each loop I want the coroutine method to finish (after retrofit responds) but my loop seem to keep going without awaiting for the coroutine method to finish.Collections are groups of a variable number of items (possibly zero) that are significant to the problem being solved and are commonly operated on.

Kotlin for each with index