Kotlin 有 array.indexOf 但我无法弄清楚如何做 array.indexOfBy { lambda }

Kotlin 有array.indexOf(item)个，但我不知道怎么做array.indexOfBy { lambda }个.它不存在吗？我可以同时获取一个项目，但无法同时获取其索引.

我在stdlib中丢失了一个函数吗？

I can create a function with a loop that chekcs the items and returns when it finds the target. Like this:

fun <T : Any> indexOfBy(items: Array<T>, predicate: (T) -> Boolean): Int {
    for (i in items.indices) { // or (i in 0..items.size-1)
        if (predicate(items[i])) {
            return i
        }
    }
    return -1
}

然后我try 使用forEach使其更具功能性:

fun <T : Any> indexOfBy(items: Array<T>, predicate: (T) -> Boolean): Int {
    (items.indices).forEach {
        if (predicate(items[it])) {
            return it
        }
    }
    return -1
}

Or I can do something silly like this which isn't very performant:

val slowAndSilly = people.indexOf(people.find { it.name == "David" })

看起来最好的可能是扩展函数:

fun <T: Any> Array<T>.indexOfBy(predicate: (T)->Boolean): Int =
        this.withIndex().find { predicate(it.value) }?.index ?: -1
fun <T: Any> Collection<T>.indexOfBy(predicate: (T)->Boolean): Int =
        this.withIndex().find { predicate(it.value) }?.index ?: -1
fun <T: Any> Sequence<T>.indexOfBy(predicate: (T)->Boolean): Int =
        this.withIndex().find { predicate(it.value) }?.index ?: -1

Is there a more elegant and idiomatic way to accomplish this?!? I also don't see a function like this for lists, collections nor sequences.

(this question is derived from the 100)