title: How to sum a row in matrix without numpy?
body: <p>How do I check the sum of a row without numpy?
  If I have this code:</p>
  
  <pre><code>Matrix = [["X", "X", "X"],[ "O", "O", "X"], ["X", "O", "X"]]
  </code></pre>
  
  <p>How do I check the sum of every row in the matrix without numpy?</p>
  
  <p>Example:</p>
  
  <p>In the matrix above my sum would be <code>x = "XXX", "OOX", "XOX"</code></p>
  
  <p><strong>EDIT</strong></p>
  
  <p>I do not like to use stuff like <code>.join</code> and <code>.map</code>.</p>