如何聚合数据帧，并按r中的重复行对列的值求和？

import pandas as pd

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

result = df.groupby(['A', 'B']).sum()

print(result)

import pandas as pd

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

result = df.groupby(['A', 'B']).sum()

print(result)