CODEWITHSUNDEEP
kotlinmapping
Yonatan Karp-Rudin
Yonatan Karp-Rudin

Reputation: 1086

Group numbers into different ranges

I'm new to Kotlin and I'm trying to solve some problem. I have a list with the following object:

data class Route(duration: Int)

I want to create a map that will group those trips according to the range of the duration (e.g. 0-9 are single group, 10-19 the next, 20-29, and so on...)

for example, the result of this list:

listOf(Route(5), Route(7), Route(31))

should be the following map:

0..9 to listOf(Route(5), Route(7))
30..39 to listOf(Route(31))

I searched and I've seen that I can put the range into groupBy - however, this is a const range. how can I group by different ranges?

Upvotes: 1

Views: 636

Answers (1)

Animesh Sahu
Animesh Sahu

Reputation: 8096

You can use the groupBy function to do that.

fun createRangeOfTen(number: Int): IntRange {
    val trunc = number / 10
    val lowerBound = trunc * 10
    val upperBound = lowerBound + 9

    return lowerBound..upperBound
}

val list = listOf(
    Route(5), Route(7), Route(31)
)
val map = list.groupBy({ createRangeOfTen(it.duration) }, { it })
println(map)
// {0..9=[Route(duration=5), Route(duration=7)], 30..39=[Route(duration=31)]}

Upvotes: 2

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