Pandas Dataframe，对按多列分组的单个值求和

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', 'two', 'two', 'one', 'two', 'one'],
        'C': [1, 2, 3, 4, 5, 6, 7, 8],
        'D': [10, 20, 30, 40, 50, 60, 70, 80]}
df = pd.DataFrame(data)

# 按列'A'和'B'进行分组，并对列'C'进行求和
sum_by_group = df.groupby(['A', 'B'])['C'].sum()

print(sum_by_group)

A    B  
bar  one    80
     two     4
foo  one     9
     two    10
Name: C, dtype: int64