在date和date上加入两个pandas数据帧

import pandas as pd

date1 = pd.DataFrame({'date': ['2022-01-01', '2022-01-02', '2022-01-03'],
                      'value1': [1, 2, 3]})
date2 = pd.DataFrame({'date': ['2022-01-04', '2022-01-05', '2022-01-06'],
                      'value2': [4, 5, 6]})

merged_date = pd.concat([date1, date2], ignore_index=True)