按日期合并多个数据框(删除重复项)

import pandas as pd

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', '2022-01-03', '2022-01-04'],
                    '数值2': [4, 5, 6]})
df3 = pd.DataFrame({'日期': ['2022-01-03', '2022-01-04', '2022-01-05'],
                    '数值3': [7, 8, 9]})

merged_df = pd.merge(df1, df2, on='日期', how='outer')
merged_df = pd.merge(merged_df, df3, on='日期', how='outer')

print(merged_df)

           日期  数值1  数值2  数值3
0  2022-01-01  1.0  NaN  NaN
1  2022-01-02  2.0  4.0  NaN
2  2022-01-03  3.0  5.0  7.0
3  2022-01-04  NaN  6.0  8.0
4  2022-01-05  NaN  NaN  9.0