Python pandas多索引选择值

import pandas as pd

# 创建一个带有多索引的DataFrame
data = {'A': [1, 2, 3, 4],
        'B': [5, 6, 7, 8],
        'C': [9, 10, 11, 12]}
index = pd.MultiIndex.from_tuples([('Group1', 'A'), ('Group1', 'B'), ('Group2', 'A'), ('Group2', 'B')])
df = pd.DataFrame(data, index=index)

# 使用loc选择多索引的值
value1 = df.loc[('Group1', 'A')]
value2 = df.loc[('Group2', 'B')]

# 使用iloc选择多索引的值
value3 = df.iloc[0]
value4 = df.iloc[3]

print(value1)  # 输出：1
print(value2)  # 输出：8
print(value3)  # 输出：A    1
               #      B    5
               #      C    9
               #      Name: (Group1, A), dtype: int64
print(value4)  # 输出：A    4
               #      B    8
               #      C    12
               #      Name: (Group2, B), dtype: int64