How to exclude some string patterns when using filter on pandas?

Question

dataframe

df.columns=['ipo_date','l2y_gg_date','l1k_kk_date']

Goal

• return dataframe with columns name containing _date except for ipo_date.

Try

• df.filter(regex='_date&^ipo_date')

Answer 1

Try a negative lookbehind:

import numpy as np
import pandas as pd

df = pd.DataFrame(np.arange(1, 21).reshape((5, 4)),
                  columns=['ipo_date', 'l2y_gg_date', 'l1k_kk_date', 'other'])

filtered = df.filter(regex=r'(?<!ipo)_date')
print(filtered)

Sample df:

   ipo_date  l2y_gg_date  l1k_kk_date  other
0         1            2            3      4
1         5            6            7      8
2         9           10           11     12
3        13           14           15     16
4        17           18           19     20

filtered:

   l2y_gg_date  l1k_kk_date
0            2            3
1            6            7
2           10           11
3           14           15
4           18           19