im really unsure why this is happening

# getting-started

[oday]

im really unsure why this is happening

[jwinwood]

Your function returns type Single<HashMap<String, List<Product>>>, toMap will return the Kotlin stdlib Map interface. HashMap is based on Java collection, and the Kotlin compiler won't know how to cast a Kotlin Map to a HashMap

[oday]

ahh...yes I thought its weird why it kept prepending Collections.... before the datatype

[jwinwood]

if your function returned Single<Map<String, List<Products>>> then toMap should work?

[oday]

Map doesnt have constructors

[jwinwood]

you can use mutableMapOf

[oday]

I think the main issue here is that the datatype returned also doesnt match the right hand side of whats being assigned in that mapping function

[oday]

i want to map the name from the json response, to a list of objects under a different field in the same json response

[jwinwood]

class Repository(
    private val apiService: ApiService
) : IRepository {
    
    override fun getProducts(): Single<Map<String, List<Product>>> =
        apiService.getProducts().map { productListings ->
            productListings.groupBy {it.name}.toMap()
        }
}

Should that not suffice?

[oday]

FDF44501-FB48-4861-B85C-6DA444D3B28F.jpg

[oday]

now its mapping the name to the rest of the parent json object, which is not Product, its ProductListing

[oday]

it does suffice, yes

[jwinwood]

class Repository(
    private val apiService: ApiService
) : IRepository {

    override fun getProducts(): Single<Map<String, List<Product>>> =
        apiService.getProducts().map { productListings ->
            val productsMap = mutableMapOf<String, List<Product>>()
            productListings.groupBy {it.name}
            productListings.foreach { listing ->
                productsMap.put(listing.name, listing.product)
            }
            productsMap
        }
}

I'm sure there is a more functional way of doing it but I think this should work

[oday]

thank you it makes total sense

[jwinwood]

no problem, glad I could help

[oday]

and it resolved all of my issues, went back to what i originally wanted, a String/List<Product> map

[oday]

thanks again

[wbertan]

data class Asas(val id: Int, val name: String)
            val list = listOf<Asas>()
            val asas: HashMap<String, List<Asas>> = HashMap(list.groupBy { it.name })

Can create a HashMap from the groupBy?! (Not tested the code above)