如何根据2个数据帧之间的公共列表元素分配列值

import pandas as pd

# 创建两个示例数据帧
df1 = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [5, 6, 7, 8], 'C': [9, 10, 11, 12]})
df2 = pd.DataFrame({'A': [1, 2, 3, 4], 'D': [13, 14, 15, 16], 'E': [17, 18, 19, 20]})

# 合并两个数据帧
merged_df = pd.merge(df1, df2, on='A')

# 获取公共列表元素
common_elements = merged_df['A'].unique()

# 遍历公共列表元素，并分配列值
for element in common_elements:
    # 根据需要的逻辑分配列值
    merged_df.loc[merged_df['A'] == element, 'B'] = merged_df.loc[merged_df['A'] == element, 'D'] + merged_df.loc[merged_df['A'] == element, 'E']

# 打印结果
print(merged_df)