Pandas, dataframe, to_csv, csvformatter

>>> df
        name    mask     weapon
0    Raphael     red    12.456734
1  Donatello  purple  13.235124
>>> df.to_csv(index=False, float_format='%.2f')
'name,mask,weapon\nRaphael,red,12.46\nDonatello,purple,13.24\n'

formatter=CSVFormatter(self, path_or_buf, ...)
formatter.save()

...
from pandas import DataFrame
...
class BW(QtGui.QMainWindow):
    ...
    def write_data_to_file(self, filename, data):
        df = DataFrame(data)
        df.to_csv(file_name, float_format = 'qweertyuiop', encoding = 'utf-8-sig', header = False, index = False, decimal = ",", index_label = False, sep = ";")

 self.write_data_to_file(csv_file_name, res)

def _on_csv_export_image_triggered(self):
                     self._widget().export_image_csv()

>>> df.to_csv(index=False,float_format='werf')
...
...
    float_format = lambda value: self.float_format % value
TypeError: not all arguments converted during string formatting

>>> df = pd.DataFrame({'a':[1.234,2.3345],'b':[3.44566,3.4566464]})
>>> df.to_csv(float_format='%.2f')
',a,b\n0,1.23,3.45\n1,2.33,3.46\n'
>>> df = pd.DataFrame({'a':[1.234,2.3345],'b':[3.44566,'3.4566464']})
>>> df.to_csv(float_format='%.2f')
',a,b\n0,1.23,3.44566\n1,2.33,3.4566464\n'