从与另一个Dataframe中的列组合不匹配的pandas Dataframe中删除行

import pandas as pd

# 假设有两个Dataframe df1和df2，需要按照列"col1"进行合并
df1 = pd.DataFrame({'col1': [1, 2, 3, 4],
                    'col2': ['A', 'B', 'C', 'D']})

df2 = pd.DataFrame({'col1': [1, 2, 5],
                    'col2': ['A', 'B', 'E']})

# 合并两个Dataframe，按照"col1"列进行匹配
merged = pd.merge(df1, df2, on='col1', how='left', indicator=True)

# 筛选出不匹配的行
unmatched_rows = merged[merged['_merge'] == 'left_only']

# 删除不匹配的行
result = df1.drop(unmatched_rows.index)

print(result)