title: Get some translations symfony2
body: <p>I get translations so:</p>
  
  <pre><code>$translated = $this-&gt;container-&gt;get('translator')
          -&gt;getCatalogue($language)
          -&gt;all();
  </code></pre>
  
  <p>But so I have all the translations.</p>
  
  <p>For example, there is a file with the following content:</p>
  
  <pre><code>symfony:
      is:
          great: Symfony is great
          amazing: Symfony is amazing
      has:
          bundles: Symfony has bundles
  user:
      login: Login
  </code></pre>
  
  <p>How can I get only certain ones (only user or only symfony)? Thanks in advance.</p>
  
  <p><strong>UPDATED:</strong>
  Did so:</p>
  
  <pre><code>$messages = [];
  foreach ($translated['messages'] as $key =&gt; $message) {
      if (stripos($key, 'frontend')) {
          $messages[$key] = $message;
      }
  }
  </code></pre>
  
  <p>But is there no such functional built in?</p>