If I have to filter a list, is it always better (performance-wise) to convert it to a flow first or ...

# announcements

[Andreas Jost]

If I have to filter a list, is it always better (performance-wise) to convert it to a flow first or did I misunderstand something?

[streetsofboston]

No, unless you really need a Flow, don't convert it to a Flow. Just keep it as a list and call filter on it. For large lists and if you call many operators on the list, you may want to convert it to a Sequence.

[streetsofboston]

Also, avoid optimizing (early) if you don't see or experience a performance issue. 😀

[Andreas Jost]

Thanks, but flows/sequences would make sense if I had a larger list of data entities and want to map it to a list of domain entities, and might also filter afterwards, right?

I will look up the difference between flow and sequence.

[streetsofboston]

Flow is a (cold) stream of data. You'd need a Coroutine to collect the data emitted by a Flow. A Sequence is a 'lazy' view on a collection (list). No need for Coroutines.

[Andreas Jost]

Understood, great explanation, thank you!

[Matteo Mirk]

If it’s not a huge list, just call list.filter {} and be fine. I support what Anton said: don’t optimize prematurely, only if you experience a slow execution.