title: How do I sample a matrix in MATLAB?
body: <p>I have a matrix in MATLAB from which I want to sample every other entry:</p>
  
  <pre><code>a =
  
       1     5     9    13
       2     6    10    14
       3     7    11    15
       4     8    12    16
  </code></pre>
  
  <p>And I want:</p>
  
  <pre><code>result =
  
       1     9    
       3    11    
  </code></pre>
  
  <p>How can I do this without a for loop?</p>