CODEWITHSUNDEEP
kotlin
userMod2
userMod2

Reputation: 8960

Kotlin - Returning list of Pair

In a Kotlin app, I have this method:

fun <VALUE> metadataOf(vararg pairs: Pair<String, VALUE>) =
    MetaData.from(pairs.toMap())!!

Which I'm then using like:

 metadataOf(
   "sId" to message.sId,
   "userId" to message.userId
)

I'm trying to write a method which can create the above for me from message - however I'm not sure how to return a list of pairs - this is what I put together based on the input parameter from metadataOf(vararg pairs: Pair<String, VALUE>)

fun metadataFrom( message: CommandMessage<Any> ): Pair<String, Any> {
     return  (
        "sId" to message.sId,
        "userId" to message.userId
        )
}

Upvotes: 0

Views: 612

Answers (1)

Giorgio Antonioli
Giorgio Antonioli

Reputation: 16224

You have two choices here.

  1. Using List:
fun metadataFrom(message: CommandMessage<Any>): List<Pair<String, Any>> = listOf(
  "sId" to message.sId,
  "userId" to message.userId
)

You can use it in this way:

val result = metadataFrom(message)
metadataOf(*result.toTypedArray())
  1. Using Array:
fun metadataFrom(message: CommandMessage<Any>): Array<Pair<String, Any>> = arrayOf(
  "sId" to message.sId,
  "userId" to message.userId
)

You can use it in this way:

val result = metadataFrom(message)
metadataOf(*result)

The second is more performant since you are directly creating the array used as input for metadataOf but nothing noticeable if you haven't a huge amount of data. So choose your favorite one.

Upvotes: 2

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