title: How can I push array inside array
body: <p>I have an array and I want to put it in another array using indexes.</p>
  
  <p>For example:</p>
  
  <pre><code>arry[1].push(sub_array_1)
  array[2].push (sub_array_2)
  </code></pre>
  
  <p>But I get an error if I write:</p>
  
  <pre><code>var sub_array_1 = [1, 2, 2, 2, 2];
  
  arry[1].push(sub_array_1)
  </code></pre>