Another viable alternative is to leverage the forEachIndexed() function, which provides a sequential index with the element and performs an action on each element. How do I iterate two lists in Kotlin I want to assign each value in one list to the equivalent textview in another list, like 1 : 1 assignment. So i already did the following: val mutablePersonsAgeChanged = mutablePersons. Output: Index: 0, Item: 4 Index: 1, Item: 2 Index: 2, Item: 5 Index: 3, Item: 4 Index: 4, Item: 1. You may also use the index property to iterate through Kotlin array as shown in the. In the following example, we take a string in str1, and iterate over each character in this string using erator() method and For Loop.

They want it to be easy but not implicit with some pre-built method, allowing to branch the computation when needed. Parallel computation trough Coroutines is no exception. Val personList = listOf(personA, personB, personC)Īnd now i'm trying to create a new list with the items from mutablePersons modified. You can see the array items are displayed without using the index property. To iterate over each character in the String in Kotlin, use erator() method which returns an iterator for characters in this string, and then use For Loop with this iterator. Kotlin wants to be idiomatic but not too much synthetic to be hard to understand at a first glance.

I did it in the following way: val personA = Person('john', 25) 1.0 fun Array.withIndex(): Iterable (source) fun ByteArray.withIndex(): Iterable (source) fun ShortArray.

So i created a new List and create a mutableList from it because i want to change their age. You will learn more about ranges in the next chapter - which will create a range of values. In Kotlin, the for loop is used to loop through arrays, ranges, and other things that contains a countable number of values. I have a data class which is: data class Person (var name : String, var age : Int)Īnd i want to create a List which contains the Person with the multiplied age multiplied per 2, only on even items. Unlike Java and other programming languages, there is no traditional for loop in Kotlin. We can understand it using the below code example.I'm playing a little bit with Kotlin and i don't understand this so, maybe someone can explain it to me. If you do not want to use the built-in functions of Kotlin Arrays to find the index of an item in Array, you can use the For Loop to find the index of an element in the array. Output Volvo index is: 4 Use For loop to find the index of an item in Array Get the index of an item in integer type values array fun main() Sometimes, one may need (or want) a loop which its iterator (the index variable) is modified within the loop body in addition to the normal incrementation.

Kotlin for each with index