title: Convert string into float python properly
body: <p>I am trying to convert the following string into float: <code>u'"0.5"'</code> but it seems that it does not work. I am trying to use <code>float(str1)</code> and I am receiving the following error: </p>
  
  <pre><code>ValueError: could not convert string to float: "0.5"
  </code></pre>
  
  <p>It seems is the way that I have stored the string. But how can I convert it into a float properly?</p>