CODEWITHSUNDEEP
kotlinfunctional-programming
Bertuz
Bertuz

Reputation: 2566

How to explode a list into a Map in kotlin?

Imagine you want to transform this:

val initialValues: List<Pair<String, String>>

where the first String represents a key, the second a value

into a map:

val finalMap: Map<String,String>

containing each pair item twice, the first with the original key, the second one with a sort of expanded key.

How would you do that? Currently I'm using a 

val finalMap = mutableMapOf<String, String>()

that I use while I'm iterating over initialValues. But I really don't like it.

initialValues.forEach {
    val explodedPairs:List<Pair<String,String>>  = <do-something> 

    explodedPairs.forEach { finalMap.put(it.first, it.second) }
}

how would you do more assertively?

Upvotes: 1

Views: 1542

Answers (3)

Michiel Leegwater
Michiel Leegwater

Reputation: 1180

You could use mapOf like this:

val initialValues: List<Pair<String, String>> = listOf()
val final = mapOf(*initialValues.toTypedArray())

But @Supriya has the better answer using toMap

Upvotes: 0

Supriya
Supriya

Reputation: 1941

You can use associate / associateBy like this - 

val map1 = initialList.associate { it.first to it.second }
println(map1.toString()) //{1=x, 2=y}

val map2 = initialList.associateBy({it.first},{it.second})
println(map2.toString()) //{1=x, 2=y}

You can also use toMap and do this - 

val map3 = initialList.toMap()
println(map3.toString()) //{1=x, 2=y}

where this is my initialList declaration - 

val initialList = listOf(Pair(1, "x"), Pair(2, "y"))

Upvotes: 5

Ge3ng
Ge3ng

Reputation: 2430

You can use associate and associateby

Upvotes: 1

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