Hello If someone could help me I m lost disappointed I need kotlinlang #announcements

Hello ! If someone could help me ... I'm lost 😞 I need to sort a list of object by multiple values. It should be first sorted based on an Int and after if a boolean is true. It's working fine when I do one (Int or boolean) with sortedWith and compareBy, but don't know how to do both. Any suggestion ?

diesieben07

07/31/2018, 11:51 AM

list.sortedWith(compareBy({ it.firstProperty }, { it.secondProperty }))

➕ 1

nikolay

07/31/2018, 11:55 AM

compareBy {
        //...
      }.thenBy() {
        //...
      }

👍 1

diesieben07

07/31/2018, 11:57 AM

Or that.

WildRhum

07/31/2018, 12:04 PM

Ty, I already tried Take version, but I get a weird error .. I tried your solution Nikolay but I can't use it with this structure it seems

diesieben07

07/31/2018, 12:05 PM

Can you show your code and the error you get please?

WildRhum

07/31/2018, 12:08 PM

Ye,s it's comming

Some contexte : I try to create a bot for a card game like hearthstone which will be like a tutorial. fun getMonsterToKill(ennemyCard: Card, myCards: List<Card>): Card{ return myCards.sortedWith(compareByDescending({ it.attack - ennemyCard.defense }, { it.abilities.contains("Divine") }))[0] }

abilities is a list of string with all the abilities of the card

diesieben07

07/31/2018, 12:16 PM

There is no

compareByDecending

with that signature.

If you need such a comparator, you need to do

compareBy(...).reversed()

However in this case you do not need to sort the whole list, just do something like this:

val comparator = compareBy<Card>({ it.attack - ennemyCard.defense }, { it.abilities.contains("Divine") })
return myCards.maxWith(comparator) ?: TODO("default value if list is empty")

❤️ 1

WildRhum

07/31/2018, 12:19 PM

Oh .. I found code with

compareBy

, so I though

compareByDecending

would work 😞

Thanks a lot ! It seems to compile 🙂 What will be the outcome of maxWith on the boolean value ? Sorted by true ?

diesieben07

07/31/2018, 12:24 PM

false

will come before

true

WildRhum

07/31/2018, 12:25 PM

Ok, so I just need to negate :

{ it.abilities.contains("Divine") }

diesieben07

07/31/2018, 12:26 PM

I can only recommend to use

in

operator here

WildRhum

07/31/2018, 12:28 PM

Oh good idea and thank you very much, it's working just as I wanted ! I'll try to help other also, guess I won't help you much 🙃

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