title: Python dataframes : select columns by name and by filter
body: <p>I want to select some columns by name, like</p>
  <pre><code>selection = df[['Name', 'Qualification']]
  </code></pre>
  <p>and some columns by a filter like</p>
  <pre><code>selection = df.filter(regex=(&quot;Level.*&quot;))
  </code></pre>
  <p>How to combine those selections in one instruction?</p>