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Asked: 2026-05-31T18:17:15+00:00

I search of method to resolve this initialization problem of tuple () with result

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I search of method to resolve this initialization problem of tuple () with result of a map, like this : 

//My current state of cities
val listOfCity = IndexedSeq(new City1(), new City2())

// Function which compute my new state
val (newCity,exchange) = listOfCity.map{ city =>  computeNewCity(city,listOfCity)}

The variable newCity contain the result ._1 of my tuple returned by computeNewCity() and the variable exchange contain the result ._2 of the same tuple.

The function computeNewCity() return a new version of my object city and an history of exchange, results of my exchange with other cities in listOfCity, it’s a tuple of type (City, Exchange)

How can i make this with help of functionnal programming ?

Thanks !
Sr

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1 Answer

  1. Editorial Team

    The problem is listOfCity.map{ city => computeNewCity(city,listOfCity)} returns an IndexedSeq[(City, Exchange)] (one tuple for each city in listOfCity), and obviously you can’t just assign it to a (City, Exchange) tuple. You could take first element or last:

    val (firstCity,exchange) = listOfCity.map{ city =>  computeNewCity(city,listOfCity)}.first

val (lastCity,exchange) = listOfCity.map{ city =>  computeNewCity(city,listOfCity)}.last

    or get a tuple of two sequences (cities and their corresponding exchanges)

    val (cities,exchanges) = listOfCity.map{ city =>  computeNewCity(city,listOfCity)}.unzip
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