Hey! I have a question: What's an idiomatic way of...

# announcements

[xii]

Hey! I have a question: What's an idiomatic way of doing this:
I have a List<Foo> fooList , and Foo has properties .isA(), isB() which returns a boolean. I receive a list of properties 'state' with elements A, B, and I have to filter the list for those properties. I'm thinking of something like this:

fooList.filter { if (state.contains('A') it.isA() else false || if (state.contains('B') it.isB() else false }

but it looks ugly

[xii]

(elements can be A and B at the same time, and the state list can contain both A and B)

[andylamax]

What do you wan't to have in the end?

[xii]

a filtered fooList based on the conditions set on the state basically

[Javier]

Something so maybe?

[alightgoesout]

you could store the filtering function if a variable:

val f = if (state.contains("A")) Foo::isA else Foo::isB
list.filter(f)

[xii]

i think i didnt explain myself properly, here's a better example:

funFilterByState(state: List<String>){
val test = ListOf(Foo("a", null), Foo (null, "b"))
return test.filter(if (state.contains("a")) it.isA() else false || if (state.contains("b") it.isB() else false)
}

data class Foo(val f: String?, val g: String?){
val isA: Boolean = f != null
val isB: Bolean = g != null}

[xii]

@alightgoesout i like that idea but doing Foo::isA casts it to any 🤔

[Michael de Kaste]

state.contains('a') && isA || state.contains('b') && isB

operator precedence and short circuiting will always result in your desired result here.

[Michael de Kaste]

if(x) a else false === x && a

[xii]

that's exactly it @Michael de Kaste, thank you! looks pretty and is functional

[araqnid]

surely you want to pull the check of state out of the filter? that is fooList.filter(if (state.contains('A')) { it.isA() } else { it.isB() })