title: Efficient way to sum an array of integers in Julia
body: <p>I have an 2D array which I want to modify so as to sum a given element in a row with all the elements before it, so for example, if I have an array:</p>
  
  <pre><code>[1 2; 3 6; 4 7; 4 8]
  </code></pre>
  
  <p>I want to be able to transform it to</p>
  
  <pre><code>[1 2; 4 8; 8 15; 12 23]
  </code></pre>
  
  <p>I can do so using the following snippet in julia:</p>
  
  <pre><code>for i in 1:10,
     for k in 2:size(d,1),
            d([k,i] += d[k-1,i)];
     end
  end
  </code></pre>
  
  <p>But I assume there must be a more efficient way to do this?</p>