如何在python中对2列使用groupby()

import pandas as pd

# 创建一个示例 DataFrame
data = {
    'A': ['foo', 'bar', 'foo', 'bar', 'foo', 'bar', 'foo', 'foo'],
    'B': ['one', 'one', 'two', 'three', 'two', 'two', 'one', 'three'],
    'C': [10, 20, 30, 40, 50, 60, 70, 80],
    'D': [1, 2, 3, 4, 5, 6, 7, 8]
}

df = pd.DataFrame(data)

# 使用 groupby() 根据列 'A' 和 'B' 进行分组
grouped = df.groupby(['A', 'B'])

# 计算每组的平均值
result = grouped.mean()

print(result)

         C         D
A   B                
bar one  20.000000  2.000000
    three 40.000000  4.000000
    two   50.000000  6.000000
foo one  40.000000  4.000000
    three 80.000000  8.000000
    two   40.000000  4.000000

# 应用自定义函数
def custom_agg(group):
    return group.max() - group.min()

result_custom = grouped.apply(custom_agg)
print(result_custom)

result_reset = result.reset_index()
print(result_reset)