guys I need to iterate over some collection but not from fir kotlinlang #announcements

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Title

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evkaky

07/10/2017, 1:14 PM

guys, I need to iterate over some collection but not from first index, and I don’t want to deal with indices at all. I know, in python there is an

enumerate(arr, fromId)

built-in function for that purpose:

for elem in enumerate(arr, 2): // elem = arr[2], arr[3] ... arr[n-1]

Is there something like that in kotlin std lib?

g

gjesse

07/10/2017, 1:54 PM

evkaky: you could write an extension function that does this for you if there isn’t one

kotlin

fun <T> Iterable<T>.enumerate(startIdx: Int): Iterable<T> {
    return this.filterIndexed { index, t -> index >= startIdx }
}

then you can do

listOf(0,1,2,3,4)
            .enumerate(2)
            .forEach {
                println(it)
            }

or you could just use filterIndexed directly 🙂

m

marstran

07/10/2017, 2:28 PM

You can use

for (n in arr.drop(2)) { .. ]

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