hey guys, i have list A and list B, I want to go o...

# getting-started

[oday]

hey guys, i have list A and list B, I want to go over B and set some property inside A depending on what I find in B, I wanna do this without 2 literal loops

[snowe]

what do you mean 'set some property'?

[oday]

like I get my own list A, then i get a list of the same type, Favorites (B), and now I want to apply an is_favorite == true on the items in list B that exist in List A

[snowe]

well I don't think there's a way to 'know' what is in list b unless you iterate over it, so you're gonna have two loops no matter what.

[oday]

i know, but I dont want to say for (

[snowe]

ah, you shouldn't be using for in kotlin anyway.

[oday]

i wouldn’t go that far

[oday]

lol

[snowe]

without knowing what your lists actually look like I can only provide small help.

[snowe]

you could use .aggregate

[snowe]

so group your A list and then aggregate to a B list

[snowe]

or you could use associateWith

[snowe]

but I'm once again unsure of what your objects look like so I'm limited in what I can come up with. (I'm a very visual person 😂 )

[oday]

here it is

searchResult.results.filter { carToMap ->
                carToMap.id == favoritesSearchResult.results.find { it.id == carToMap.id }?.id
            }.map { it.is_favorite = true }

[snowe]

sorry, been very busy. let me look

[snowe]

oh is that your solution?

[ilya.gorbunov]

You can collect favorites or favorite ids into set and then use contains of that set:

val favoriteIds = favoritesSearchResult.results.map { it.id }.toSet()
searchResult.results.forEach {
    it.is_favorite = it.id in favoriteIds
}

[oday]

sure yes

[oday]

of course you could do that