title: Convert percent string to float in pandas read_csv
body: <p><strong>Is there a way to convert values like '34%' directly to int or float when using read_csv in pandas?</strong> I want '34%' to be directly read as 0.34</p>
  <ol>
  <li><p>Using this in <code>read_csv</code> did not work:</p>
  <p><code>read_csv(..., dtype={'col':np.float})</code></p>
  </li>
  <li><p>After loading the csv as 'df' this also did not work with the error &quot;invalid literal for float(): 34%&quot;</p>
  <p><code>df['col'] = df['col'].astype(float)</code></p>
  </li>
  <li><p>I ended up using this which works but is long winded:</p>
  <p><code>df['col'] = df['col'].apply(lambda x: np.nan if x in ['-'] else x[:-1]).astype(float)/100</code></p>
  </li>
  </ol>