Most operators can be called in their function for...

# announcements

[Florian]

Most operators can be called in their function form, like 1.plus(2). Is there also a form like this for in when it uses iterator (not contains)?

[diesieben07]

You already found it, it's called iterator 😛

[diesieben07]

That returns an Iterator which you can then traverse using hasNext and next calls

[kralli]

As Take correctly said, in stands for iterator(). So what exactly are you trying to achieve?

[kralli]

If you are looking for a different way to loop, then iterator.forEach { } might be a solution.

[Florian]

I mean that you can use the other operators in their function form

[Florian]

but for iterator this doesnt seem possible

[Florian]

its a theoretical question

[diesieben07]

Yes, it is possible. https://pl.kotl.in/ZiaruOtUr

[Florian]

I mean directly in this construct (i in 1..10)

[Florian]

you cant call i.iterator(1..10) or something like that

[Florian]

other operators can be replaced directly like this

[Florian]

1 + 2 -> 1.plus(2)

[Florian]

1..10 -> 1.rangeTo(10)

[diesieben07]

val it = (1..10).iterator()

[Florian]

I see

[diesieben07]

And then you have, again, an Iterator which you can go through using for...in or hasNext() and next()

[diesieben07]

https://pl.kotl.in/plOhU92Yg

[Florian]

ok thank you

[Dico]

You can only do for (i in iterator)
Because the stdlib has
fun Iterator<T>.iterator() = this

[Florian]

yea thats what I mean, it's a bit different because Ctrl+B on in brings me to the iterator function

[Florian]

but it doesn't actually replace it in the code

[Ryan Mentley]

it's translated to contains

[Ryan Mentley]

There's an `operator fun Iterable.contains`: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/contains.html

[Ryan Mentley]

so yes, you can call it yourself: just call someObject.contains(someOtherObject)

[diesieben07]

@Florian What do you mean by "doesn't actually replace it in the code"?

[Florian]

@Ryan But I am talking about iteration

[Florian]

It doesn't replace the "in" keyword

[diesieben07]

The for...in construct compiles to several method calls: One call to iterator and then a while loop that repeatedly calls next until hasNext returns false.

[diesieben07]

The in cannot be replaced by just a single method call.

[Florian]

yea that's what I wanted to clarify