title: PHP array_push one array into another
body: <p>I need to add one array inside of another using array_push or something similar.</p>
  
  <p>What I would like to achieve will look like this:</p>
  
  <pre><code>$years = array(
      "2017" =&gt; array("Value01", "Value02"),
      "2016" =&gt; array("Value03")
  );
  </code></pre>
  
  <p>What would be the best way to create an array within another? I have tried the following:</p>
  
  <pre><code>array_push($years, "2016" =&gt; array());
  </code></pre>
  
  <p>This just gives a </p>
  
  <blockquote>
    <p>500 error.</p>
  </blockquote>
  
  <p>And:</p>
  
  <pre><code>array_push($years, "2016");
  </code></pre>
  
  <p>This does add a new array within $yearshowever it is called "2018" and the "2016" value is place inside that 2018 array. I have manually created the 2017 array already, so I assume it is just incrementing on that number for some reason.</p>