title: Checking if 2 arrays have at least 1 equal value
body: <p>Currently I have 2 array:</p>
  
  <pre><code>array(1, 2, 3, 4);
  array(4, 5, 6, 7);
  </code></pre>
  
  <p>How can I check if there is at least one equal value in both of them? (The example above has 1 equal value => 4, so the function should return true).</p>