从不同数据帧(不同长度)的列中追加标识datetime匹配日期的新列

import pandas as pd
from datetime import datetime

# 创建示例数据帧
df1 = pd.DataFrame({'日期': ['2022-01-01', '2022-01-02', '2022-01-03'], '数值1': [1, 2, 3]})
df2 = pd.DataFrame({'日期': ['2022-01-02', '2022-01-04'], '数值2': [4, 5]})

# 将日期列转换为datetime对象
df1['日期'] = pd.to_datetime(df1['日期'])
df2['日期'] = pd.to_datetime(df2['日期'])

# 创建新列
df1['匹配日期'] = ''

# 遍历df1的日期列
for index, row in df1.iterrows():
    target_date = row['日期']
    
    # 遍历df2的日期列
    for index2, row2 in df2.iterrows():
        compare_date = row2['日期']
        
        # 比较日期
        if target_date == compare_date:
            df1.at[index, '匹配日期'] = row2['数值2']
            break

print(df1)

          日期  数值1 匹配日期
0 2022-01-01     1     
1 2022-01-02     2    4
2 2022-01-03     3