Python-如何从multiIndexed数据框中选择行

import pandas as pd

# 创建一个示例的multiIndexed数据框
data = {'A': [1, 2, 3, 4],
        'B': [5, 6, 7, 8]}
index = pd.MultiIndex.from_tuples([('group1', 'subgroup1'),
                                   ('group1', 'subgroup2'),
                                   ('group2', 'subgroup1'),
                                   ('group2', 'subgroup2')],
                                  names=['level1', 'level2'])
df = pd.DataFrame(data, index=index)

# 使用loc方法选择行
selected_rows = df.loc[('group1', 'subgroup1')]
print(selected_rows)

A    1
B    5
Name: (group1, subgroup1), dtype: int64

selected_rows = df.loc[('group1', 'subgroup1'):('group1', 'subgroup2')]
print(selected_rows)

                 A  B
level1 level2        
group1 subgroup1  1  5
group1 subgroup2  2  6

selected_rows = df.loc[df['A'] > 2]
print(selected_rows)

                 A  B
level1 level2        
group2 subgroup1  3  7
group2 subgroup2  4  8