— Does DataFrame.replace() allow to replace the whole column?
Ok. Let's try it another way. How to clean the csv file of strings which contain whitespaces all at once? I mean without using loops since it slows down the process dramatically. I have got enormous csv's
— Did you try chunk['Кол-во'] = pd.core.series.Series([np.float64(x.strip().replace(',','.')) for x in chunk['Кол-во']]) ?