Is there findFirst with position in predicate in Kotlin

Issue

I need to find first element in a list which fits predicate. But I need to check with it position in predicate.

    list.findXXX { index, item ->
        index > 19 && item.active
    }

Is there such a function?

Solution

There is no such function yet, but you can easily write one yourself. It is not a lot of effort at all.

public inline fun <T> Iterable<T>.findIndexed(predicate: (Int, T) -> Boolean): T? {
    forEachIndexed { i, e -> if (predicate(i, e)) return e }
    return null
}

Alternatively, in general you can use a filterIndexed to first filter out the indexes that you want to exclude:

list
//  .asSequence() // if you want to be lazy
    .filterIndexed { i, _ -> i > 19 }
    .find { item -> item.active }

In fact, you could just put the entire condition in filterIndexed and use firstOrNull afterwards. It just may not read as nicely as find.

Of course in this specific case you can also just drop the first 20.

Answered By - Sweeper