title: return values where key contains this string
body: <p>I have an array like this:</p>
  
  <pre><code>array(
      [root_1] =&gt; array(
          [level_1] =&gt; array(
              [id_1] =&gt; array(
                  [foo] = bar
              )
          )
      )
  )
  </code></pre>
  
  <p>Where I know the names (i.e root, level and id) but I do not know the number part of the key.</p>
  
  <p>I need a function that can return any parts of the array where the key contains a given name.</p>
  
  <p>Cheers</p>