如何在Python中按一个键对多个键进行分组？

import pandas as pd

# 创建一个示例DataFrame
data = {
    'Key1': ['A', 'A', 'B', 'B', 'A'],
    'Key2': [1, 2, 1, 2, 1],
    'Value1': [10, 20, 30, 40, 50],
    'Value2': [100, 200, 300, 400, 500]
}

df = pd.DataFrame(data)

# 根据'Key1'进行分组，并计算'Value1'和'Value2'的平均值
grouped = df.groupby('Key1').agg({'Value1': 'mean', 'Value2': 'mean'})

print(grouped)

       Value1  Value2
Key1                  
A      26.666667  266.666667
B      35.000000  350.000000

grouped_multi = df.groupby(['Key1', 'Key2']).agg({'Value1': 'mean', 'Value2': 'mean'})

# 迭代分组
for name, group in grouped_multi:
    print(name)
    print(group)

# 使用transform计算每个组的总和
df['Value1_sum'] = df.groupby('Key1')['Value1'].transform('sum')

df_cleaned = df.dropna()
grouped_cleaned = df_cleaned.groupby('Key1').agg({'Value1': 'mean', 'Value2': 'mean'})