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    <p>I can't tell from your code what you actually want to do.</p> <p>If you want traverse your array with iterators of iterators, there's already an easy way to do it:</p> <pre><code>val a2d = Array.tabulate(4,4)((i,j)=&gt;4*i+j) a2d.iterator.map(_.iterator) </code></pre> <p>And if you decide you want a single iterator, you can do that too:</p> <pre><code>a2d.iterator.flatMap(_.iterator) </code></pre> <p>If you want to traverse <em>columns</em> even though the array is in row-major order, then you have a little more work to do (which I think is what you were trying to do, but you mixed up your array indices, and maybe some other things):</p> <pre><code>def iterateColumns(aai: Array[Array[Int]]) = new Iterator[Iterator[Int]] { private[this] var j = -1 private[this] val shortest = if (aai.length==0) 0 else aai.map(_.length).min def hasNext = j+1 &lt; shortest def next = { j += 1 new Iterator[Int] { private[this] var i = -1 def hasNext = i+1 &lt; aai.length def next = { i += 1 aai(i)(j) } } } } </code></pre> <p>Now you can</p> <pre><code>scala&gt; for (row &lt;- a2d.iterator.map(_.iterator)) println(row.mkString(" ")) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 scala&gt; for (col &lt;- iterateColumns(a2d)) println(col.mkString(" ")) 0 4 8 12 1 5 9 13 2 6 10 14 3 7 11 15 </code></pre> <p>(You also ought to be able to do <code>a2d.view.transpose.iterator.map(_.iterator)</code> to avoid making a copy, but unfortunately it doesn't look like this works the way you'd hope in 2.8.1.)</p>
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