title: Find the most common value in array
body: <p>I have a multi dimensional array that looks like this:</p>
  
  <pre><code>[
     [ 30,  40   ]
     [ 40,  40   ]
     [ 100, 100  ]
     [ 100, 100  ]
     [ 100, 100  ]
     [ 200, 100  ]
     [ 200, 200  ]
  
  ]
  </code></pre>
  
  <p>How can I get the value pair that is the most common from it - <code>[100, 100]</code> ?</p>