title: How to sum every couple of consecutive elements in an array?
body: <p>I have an array of size <code>(1,10)</code>:</p>
  <pre><code>A = [1 2 3 4 5 6 7 8 9 10]
  </code></pre>
  <p>Now I want to compute a new array with size <code>(1,5)</code> as:</p>
  <pre><code>B = [3 7 11 15 19]
  </code></pre>
  <p>Which is constructed by:</p>
  <pre><code>3 = 1 + 2
  7 = 3 + 4
  ...
  19 = 9 + 10
  </code></pre>
  <p>How can I implement it in Python?</p>