将pandas多索引折叠为单个索引

import pandas as pd

# 创建一个带有多级索引的DataFrame
data = {'A': [1, 2, 3, 4],
        'B': [5, 6, 7, 8]}
index = pd.MultiIndex.from_tuples([('Group1', 'A'), ('Group1', 'B'), ('Group2', 'A'), ('Group2', 'B')])
df = pd.DataFrame(data, index=index)

# 折叠多索引为单索引
df = df.reset_index()

print(df)

   level_0 level_1  A  B
0   Group1       A  1  5
1   Group1       B  2  6
2   Group2       A  3  7
3   Group2       B  4  8