如何高效地在多个列中使用value_counts？

import pandas as pd

# 创建一个包含多个列的DataFrame
data = {'A': ['foo', 'bar', 'foo', 'bar', 'foo', 'bar'],
        'B': ['one', 'one', 'two', 'two', 'two', 'one'],
        'C': [1, 2, 3, 4, 5, 6]}
df = pd.DataFrame(data)

# 在多个列中使用value_counts
counts = df.groupby(['A', 'B']).size()

print(counts)

A    B  
bar  one    2
     two    1
foo  one    1
     two    2
dtype: int64