pandas 一个小坑

import pandas as pd


df = pd.DataFrame([
	{'a': 1, 'b': 2},
	{'a': 11, 'b': 2},
	{'a': 111, 'b': 222},
])

# df = df[(z20m_collection_df['a'] != 1) & (df['b'] != 2)]
#      a    b
# 2  111  222

# df = df[~((z20m_collection_df['a'] == 1) & (df['b'] == 2))]
#      a    b
# 1   11    2
# 2  111  222

# df = df[(df['a'] == 1) & (df['b'] == 2)]
#    a  b
# 0  1  2

# df = df[(df['a'] != 1) & (df['b'] == 2)]
#     a  b
# 1  11  2