Be careful with those functions on large collections, though. Most of them will copy the collection for the sake of immutability.

Functions starting with as won't do that, though:

// Returns a view, no copy here
(1..10).toList().asReversed()

// Same here
(1..10).toList().asSequence()

To understand the difference, check the following code:

val numbers = (1..1_000_000).toList()
println(measureTimeMillis {
    numbers.stream().map {
        it * it
    }
}) // ~2ms

println(measureTimeMillis {
    numbers.map {
        it * it
    }
}) // ~19ms

You'll notice that code using stream() actually never executes. Streams, being lazy, wait for a terminating function call. Functions on collections, on the other hand, execute one after the other.

If we add the terminating call though, we'll see totally different numbers:

println(measureTimeMillis {
    numbers.stream().map {
        it * it
    }.toList()
}) // ~70ms

Converting from the stream back to the list is an expensive operation. Take those points into consideration when deciding which approach to use.