title: Unable to convert a unicode data to float
body: <p>I have downloaded a data set in xml format from online webpage. I have extracted the values tag using pattern library of python. This gives me unicode values.</p>
  
  <p>I am looking to convert this unicode number, like u'63.3' to a float number. I have tried doing float(a) but it gives error messages. </p>
  
  <pre><code>import numpy as np
  import pandas as pd
  import requests
  from pattern import web
  
  xml = requests.get('http://charts.realclearpolitics.com/charts/1044.xml').text
  dom = web.Element(xml)
  values = dom.by_tag('value')
  
  date= []
  approve = []
  disapprove = []
  
  values = dom.by_tag('value')
  for i in range(0,1724):
      date.append(pd.to_datetime(values[i].content))
  
  for i in range(1724,3448):
      a = float(values[i].content)
      approve.append(a)
  
  for i in range(3448,5172):
      a = float(values[i].content)
      disapprove.append(a)
  
  finalresult = pd.DataFrame({'date': date, 'Approve': approve, 'Disapprove': disapprove})
  finalresult
  </code></pre>
  
  <p>Output is as follows:     </p>
  
  <pre><code>---------------------------------------------------------------------------
  ValueError                                Traceback (most recent call last)
  &lt;ipython-input-12-d9d9e580d883&gt; in &lt;module&gt;()
        9 
       10 for i in range(1724,3448):
  ---&gt; 11     a = float(values[i].content)
       12     result['Approve'].append(a)
       13 
      ValueError: could not convert string to float:
  </code></pre>