hi gang, is there any nice, easily understandable/...

# codereview

[czuckie]

hi gang, is there any nice, easily understandable/identifiable way to turn a list of Byte (List<Byte>) into a list of Shorts? (List<Short>) such that [ 0x10, 0x01 ] would become [ 0x1001 ]

[czuckie]

private fun List<Byte>.toShorts(): List<Short> {
    val result = mutableListOf<Short>()
    for (i in 0 .. size - 2 step 2) {
        result.add((this[i].toInt().shl(8) + this[i+1]).toShort())
    }
    return result
}

Is what I've got, which is I guess understandable, but I wonder if there is a more kotlin'y way to iterate over pairs of list items to them map them into something else

[bezrukov]

Use windowed/chunked to split the list into pairs and then map them to shorts (but it is less efficient than your initial option, if you care about it)

[ephemient]

you can simplify the loop in your function to

for (i in indices step 2) {

or change indexing to something which also pre-sizes the output

List(size / 2) { i ->
    (this[2 * i].toUInt() shl 8 or this[2 * i + 1].toUInt()).toShort()
}

[czuckie]

cheers guys! I like the windowing approach, I didn't even consider that, but didn't realise i in indices was a thing either.