is there a way to create a single element `Iterabl...

# announcements

[bj0]

is there a way to create a single element Iterable without creating an array or list?

[adam-mcneilly]

What's the benefit of this?

[Travis]

Same, curious, to what end?

[Travis]

listOf(element) would be iterable, but it builds a list…

[adam-mcneilly]

^ which is what I wanted to suggest, but I don't understand what blocker the list causes

[bj0]

i'm using a when condition inside a flatMap, most of the conditions return lists but one has a single element, I was wondering if there was something without the (probably very low) overhead of creating an unnecessary list/array

[bj0]

it's not a blocker, It just seems unnecessary

[bj0]

so I was wondering if there was something similar to .just() from Rx

[adam-mcneilly]

What's the ultimate return type here? If all cases return a list, I would expect the calling code to expect a list to be returned, but if there's a case for only one then your calling code might get ugly?

Side note: Loosely wondering if a sealed class could work here, but don't know if there's enough context.

[Travis]

the analog appears to be that, listOf(element) - I mean, Observable.just still creates an Observable…

[bj0]

flatMap expects an Iterable

[Travis]

Yeah, gonna need more context here

[adam-mcneilly]

it's a good question, and I'm curious to see if someone thinks of anything, but I wouldn't argue that the list creation is too much overhead to stress if you don't get an answer. ¯\_(ツ)_/¯

[bj0]

yea I didn't know if there was a lightweight wrapper around a value that implemented Iterable, but I don't see anything like that

[bj0]

It's not a lot, like I said, I was just curious, I'm fine using listOf

[bj0]

but the context is replacing some bytes with multiple bytes in a bytestream, hence the flatMap, and flatMap requires an Iterable<T>

[paulblessing]

listOf() with a single item ultimately creates a java.util.SingletonList (on the JVM at least) which is a very lightweight list implementation.

[bj0]

good to know