How can i get the indices of items in a list that match a condition?

# android

[Gunis]

How can i get the indices of items in a list that match a condition?

[Tim Malseed]

I might do something like

list.mapIndexedNotNull { index, item ->
      if (item == condition) {
          Pair(index, item)
      } else {
          null
      }
  }

[Al Warren]

val numbers = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9)

val indices = numbers.indices
    .filter { numbers[it] % 2 == 0 }

println(indices)
println(numbers.slice(indices))

// output
// [1, 3, 5, 7]
// [2, 4, 6, 8]

[Tim Malseed]

Oh, that’s much nicer