Scala Array.copyToArray source start index [duplicate]

Question

Can I copy from one Array[T] to another and specify the source start index?

val a = (1 to 10).toArray
val b = new Array[Int](8)
// specify target array, destination start index, and length.
// can i specify source start index?
a.copyToArray(b, 3, 2)

// b = Array[Int] = Array(0, 0, 0, 1, 2, 0, 0, 0)

So, I can use Array.drop to get the desired behavior, however that seems inefficient?

Yuchen · Accepted Answer · 2017-09-03 16:58:51Z

1

How about using slice?

val sourceStartIndex = 1
val destinationStartIndex = 3
val length = 2
a.slice(sourceStartIndex, sourceStartIndex + length)
 .copyToArray(b, destinationStartIndex, length)

It'll be more efficient than drop if length is small.

answered Sep 3, 2017 at 16:58

Yuchen

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Dima · Accepted Answer · 2017-09-03 17:39:54Z

0

I think, you are looking for Array.copy(a, srcStart, b, 3, 2)

answered Sep 3, 2017 at 17:39

Dima

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