How to specify date format when using pandas.to_csv?

Since version v0.13.0 (January 3, 2014) of Pandas you can use the date_format parameter of the to_csv method:

df.to_csv(filename, date_format='%Y%m%d')

You could use strftime to save these as separate columns:

df['date'] = df['datetime'].apply(lambda x: x.strftime('%d%m%Y'))
df['time'] = df['datetime'].apply(lambda x: x.strftime('%H%M%S'))

and then be specific about which columns to export to csv:

df[['date', 'time', ... ]].to_csv('df.csv')