title: Boolean indexing to find character
body: <p>I have a column in a pandas DataFrame called 'line' that is either a string representation of a number, or a string representation of two numbers separated by the '&amp;' symbol. So I want to find the index points of all the observations that have '&amp;' in the 'line' column. </p>
  
  <p>I know I can do this:</p>
  
  <pre><code>index_points = []
  for row in df.index:
      if '&amp;' in df.loc[row, 'line']:
          index_points.append(row)
  </code></pre>
  
  <p>But i don't like it. Is there a better way?</p>