pandas - 如何在 Pandas 中创建日历表(日期维度)

Question

具有主键的日期表有时在数据库设计中使用。

| date_id |     Date       |    Record_timestamp |  Day      |  Week |  Month |     Quarter |   Year_half |     Year |
|---------+----------------+---------------------+-----------+-------+--------+-------------+-------------+----------|
|       0 |     2000-01-01 |    NaN              |  Saturday |  52   |  1     |     1       |   1         |     2000 |
|       1 |     2000-01-02 |    NaN              |  Sunday   |  52   |  1     |     1       |   1         |     2000 |
|       2 |     2000-01-03 |    NaN              |  Monday   |  1    |  1     |     1       |   1         |     2000 |

在 Pandas 中怎么做？

Answer 1

使用 dt accessor可以使它更干净:

In [11]: def create_date_table2(start='2000-01-01', end='2050-12-31'):
    ...:     df = pd.DataFrame({"Date": pd.date_range(start, end)})
    ...:     df["Day"] = df.Date.dt.weekday_name
    ...:     df["Week"] = df.Date.dt.weekofyear
    ...:     df["Quarter"] = df.Date.dt.quarter
    ...:     df["Year"] = df.Date.dt.year
    ...:     df["Year_half"] = (df.Quarter + 1) // 2
    ...:     return df

In [12]: create_date_table2().head()
Out[12]:
        Date        Day  Week  Quarter  Year  Year_half
0 2000-01-01   Saturday    52        1  2000          1
1 2000-01-02     Sunday    52        1  2000          1
2 2000-01-03     Monday     1        1  2000          1
3 2000-01-04    Tuesday     1        1  2000          1
4 2000-01-05  Wednesday     1        1  2000          1

In [13]: create_date_table2().tail()
Out[13]:
            Date        Day  Week  Quarter  Year  Year_half
18623 2050-12-27    Tuesday    52        4  2050          2
18624 2050-12-28  Wednesday    52        4  2050          2
18625 2050-12-29   Thursday    52        4  2050          2
18626 2050-12-30     Friday    52        4  2050          2
18627 2050-12-31   Saturday    52        4  2050          2

注意:您可能想即时计算它们，而不是将它们存储为列!