title: Python pandas doesn't recognize special characters
body: <p>I am trying to use <code>df['column_name'].str.count("+")</code> in python pandas, but I receive </p>
  
  <blockquote>
    <p>"error: nothing to repeat"</p>
  </blockquote>
  
  <p>. With the regular characters the method works, e.g. <code>df['column_name'].str.count("a")</code> works fine.</p>
  
  <p>Also, there is a problem with the "^"-sign. If I use <code>df['column_name'].str.contains("^")</code> the result is incorrect - it looks like "^" gets interpreted as " " (empty space).</p>
  
  <p>Surprisingly, if I use <code>.count("+")</code> and <code>.contains("^")</code> on a regular, non-pandas string they work perfectly fine.</p>
  
  <p>simple working example:</p>
  
  <pre><code>df = pd.DataFrame({'column1': ['Nighthawks+', 'Dragoons'], 'column2': ['1st', '2nd']}, columns = ['column1', 'column2'])
  </code></pre>
  
  <p>When applying <code>df["column1"].str.contains("^")</code> one gets "True, True" but is should be "False, False".</p>
  
  <p>And when applying <code>df["column1"].str.count("+")</code> one gets </p>
  
  <blockquote>
    <p>"error: nothing to repeat"</p>
  </blockquote>
  
  <p>But then, outside of panda, <code>"bla++".count("+")</code> gives correctly the result "2".</p>
  
  <p>Any solutions? Thanks</p>