df = pd.DataFrame({'col1':pd.date_range('2015-01-02 15:00:07', periods=3),
'col2':pd.date_range('2015-05-02 15:00:07', periods=3),
'col3':pd.date_range('2015-04-02 15:00:07', periods=3),
'col4':pd.date_range('2015-09-02 15:00:07', periods=3),
'col5':[5,3,6],
'col6':[7,4,3]})
print (df)
col1 col2 col3 \
0 2015-01-02 15:00:07 2015-05-02 15:00:07 2015-04-02 15:00:07
1 2015-01-03 15:00:07 2015-05-03 15:00:07 2015-04-03 15:00:07
2 2015-01-04 15:00:07 2015-05-04 15:00:07 2015-04-04 15:00:07
col4 col5 col6
0 2015-09-02 15:00:07 5 7
1 2015-09-03 15:00:07 3 4
2 2015-09-04 15:00:07 6 3
list_of_cols_to_change = ['col1','col2','col3','col4']
df[list_of_cols_to_change] = df[list_of_cols_to_change].apply(lambda x: x.dt.date)
print (df)
col1 col2 col3 col4 col5 col6
0 2015-01-02 2015-05-02 2015-04-02 2015-09-02 5 7
1 2015-01-03 2015-05-03 2015-04-03 2015-09-03 3 4
2 2015-01-04 2015-05-04 2015-04-04 2015-09-04 6 3