Sequences

Suspending sequences are quite different from suspending iterators, so let's take a look at some of the characteristics of suspending sequences:

• They can retrieve a value by index
• They are stateless, and they reset automatically after being interacted with
• You can take a group of values with a single call

In order to create a suspending sequence, we will use the builder buildSequence(). This builder takes a suspending lambda and returns a Sequence<T>, where T can be inferred by the elements that are yielded, as for example the following:

val sequence = buildSequence { 
yield(1)
}

This will make the sequence a Sequence<Int>. But, similar to iterators, you can always specify a T as long as the values that are yielded are compliant:

val sequence: Sequence<Any> = buildSequence { 
yield("A")
yield(1)
yield(32L)
}

Interacting with a sequence

Consider the following sequence:

val sequence = buildSequence {
yield(1)
yield(1)
yield(2)
yield(3)
yield(5)
yield(8)
yield(13)
yield(21...