Kotlin for loop is equivalent to the foreach loop in languages like C.

that contains a countable number of values, for example arrays, ranges, maps or any other collection available in Kotlin. I came up with these general functions: fun forloop(state: S, condition: (s: S) -> Boolean, postExecution: (s: S) -> Unit, block: (s: S) -> Unit) ')Īlthough, in compliance with the language philosophy, you should only use this in rare circumstances. Kotlin for loop iterates through anything that provides an iterator ie. So, we can iterate through it using for loop. Remember we can iterate through anything using kotlin for loop if it provides iterator. However, I needed a traditional for loop (like java) with an immediately terminating state scope, exit condition that evaluates before loop-body execution, and a post-execution operation (my use case was complicated: I needed to repeat using a dynamic exit condition based on a compression routine and powers of 2). In Kotlin, you can use for loop to iterate through following things Range Array String Collection. You may need to decipher that every time you come back to it.Kotlin is trying to enforce fluent iteration, which covers the vast majority of looping constructs. The indices/ mapIndexed-solution rather hide what's going on. It's way easier to read when you come back.

And I can only recommend you to use the flatMap instead. Depending on how complex your condition is, the indices themselvses will not suffice you. Note that if what you are trying to insert is static, solution with the indices is of course easier then the mapping I've presented above. It should be easy enough though to add that case. indexOf returns -1 or itemsToInsertAfterMatch = null). In the following example, we are iterating through array list of planets and printing each. what is matched with what? and what is inserted when where?).Īll the above solutions did not yet deal with the case when an element wasn't found (e.g. We can use for loop to iterate through an arraylist in Kotlin. For example, a range, array, string, etc. The for loop in Kotlin can be used to iterate through anything that provides an iterator. In Kotlin, the for loop works like the forEach in C. If you do not must (and who forces you?), I wouldn't use such a construct. Generally, the for loop is used to iterate through the given block of code for the specified number of times. As you said you iterate over the list, maybe a flatMap is rather something for you (in this example I add 'odd', 'even' after elements that are odd/even): val list = listOf('1', '2', '3', '4')Ġ -> listOf(it, ' listOf(it, ' itemsToInsertAfterMatch?.let

For loop kotlin with index