title: Ruby array each_slice_with_index?
body: <p>If I have <code>arr = [1, 2, 3, 4]</code> I know I can do the following...</p>
  
  <pre><code>&gt; arr.each_slice(2) { |a, b| puts "#{a}, #{b}" }
  1, 2
  3, 4
  </code></pre>
  
  <p>...And...</p>
  
  <pre><code>&gt; arr.each_with_index { |x, i| puts "#{i} - #{x}" }
  0 - 1
  1 - 2
  2 - 3
  3 - 4
  </code></pre>
  
  <p>...But is there a built in way to do this?</p>
  
  <pre><code>&gt; arr.each_slice_with_index(2) { |i, a, b| puts "#{i} - #{a}, #{b}" }
  0 - 1, 2
  2 - 3, 4
  </code></pre>
  
  <p>I know I can built my own and stick it into the array method. Just looking to see if there is a built in function to do this.</p>