Learning Kotlin Programming

Kotlin Flow a much better version of Sequence?

Do we still need Sequence, after we have Flow?

Photo by Johann Walter Bantz on Unsplash

Sometime back, I’m curious how is List different from Sequence. I explored into it, and notice Sequence is Lazy and List is Slow. Each have their advantage.

Kotlin : Slow List and Lazy Sequence

With Kotlin Flow now in place, it behaves like a Sequence.

runBlocking {
    (1..3).asSequence()
        .map { println("sequence mapping $it"); it * 2 }
        .first { it > 2 }
        .let { println("sequence $it") }

    (1..3).asFlow()
        .map { println("flow mapping $it"); it * 2 }
        .first { it > 2 }
        .let { println("flow result $it") }
}

For the code above, both also behave like below

It will lazily process each item and terminate the process as soon as it get the result.