title: Remove double quotes from data frame while writing to csv
body: <p>I tried to include 3 lists into dictionary, convert to data frame and then write to csv</p>
  
  <pre class="lang-py prettyprint-override"><code>dicti = {'X': list_X, 'Y': list_Y, 'Z': list_Z} 
  df2 = pd.DataFrame(dicti) 
  df2.to_csv('dataa.csv')
  </code></pre>
  
  <p>Output printed in csv</p>
  
  <pre><code>"9.0, 9.0, 2.5, 1.5811388300841898, 1.2","10.0, 10.0, 2.5, 1.5811388300841898, 1.2","18.0, 18.0, 2.5, 1.5811388300841898, 1.2"
  </code></pre>
  
  <p>Expected output</p>
  
  <pre><code>9.0, 9.0, 2.5, 1.5811388300841898, 1.2,10.0, 10.0, 2.5, 1.5811388300841898, 1.2,18.0, 18.0, 2.5, 1.5811388300841898, 1.2
  </code></pre>