How to use various higher-order functions with the List collection, including forEach(). Related Query Kotlin foreach return list Return list outside ForEach loop return only last item in Kotlin Am I having Kotlin functions return a List. If you find any problems with my methodology and/or results, please let me know and I will update the article. Knowledge of various collection types in Kotlin, such as List.

Hopefully, this rumination on for-loops was illuminating - it’s as exciting as I could make it. What about iterating over arrays Given nums: Array, we have two choices.

Practical differences in efficiency are minimal but may be enough to sway you one way or another if you were looking for any difference at all.

In order to create a mutable list, MutableList interface needs to be used. 5 Ways to Iterate Over a List in Kotlin Using forEach () method Using for loop An alternative for cycle utilizes the size of the list Using forEachIndexed () method Using a ListIterator and a while loop Here is a complete source code to demonstrate five ways of looping over a list in Kotlin. • Both are identical when used on arrays, lists and other iterables Attribute Array List Implementation: Array is implemented using Array class: List or MutableList interfaces are used to implement a List in Kotlin Mutable: Array is mutable, i.e., the values can be changed.

Functional forEach allocates one or two more objects on numeric ranges (depending on the conditions) but somewhat more consistent, especially when used around other functional operations (e.g.

Traditional for-loops are slightly more memory efficient on numeric ranges and probably more readable for Java developers, albeit less “functional”.

The same would apply to all other implementations of Iterable, including built-in types and anything custom you may conjure.

Traditional for-loop: for (i in 0.10).

* Performs the given on each inline fun Iterable.Let’s say you want to loop over a range of integers, you have two options:

If you look at the definition of forEach, you'll find: /**

Kotlin list foreach