title: Integer array to binary array
body: <p>I have an integer array:</p>
  
  <pre><code>a=[3,4,5,6,7];
  </code></pre>
  
  <p>I want to convert it to a binary array with four bits each. For the above integer array I would like get the following binary array:</p>
  
  <pre><code>abinary=[0,0,1,1, 0,1,0,0, 0,1,0,1, 0,1,1,0, 0,1,1,1];
  </code></pre>
  
  <p>Is there any fast way to do it?</p>