日期时间到季节

Question

我有一个示例数据：

datetime.            column1

2021-04-01 01:00.     11
2021-04-05 02:00.     10
2021-04-12 03:00.      1
2021-04-11 04:00.      5
2021-04-07 05:00.      20

我想创建一个名为 season 的新列，如果日期时间值介于 5 月和 9 月之间，则输出冷却季节，如果日期时间值介于 10 月和 4 月之间，则输出采暖季节。示例输出应如下所示：

datetime.            column1.  seasons

2021-01-01 01:00.     11.       Heating season
2021-05-01 02:00.     10.       Cooling season
2021-12-01 03:00.      1.       Heating season
2021-11-01 04:00.      5.       Heating season
2021-07-01 05:00.      20.      Cooling season

Answer 1

有很多方法，

df['datetime'] = pd.to_datetime(df.datetime)

使用 np.select 和几个月的特定条件

conditions = [
    df.datetime.dt.month.isin(np.arange(5,10)),
    (df.datetime.dt.month.isin(np.arange(1,5))) | (df.datetime.dt.month.isin(np.arange(10,13))),
]
choices = ['Cooling season','Heating season']
df['seasons'] = np.select(conditions, choices)
df

使用带有默认值的 np.select

conditions = [
    df.datetime.dt.month.isin(np.arange(5,10)),
]
choices = ['Cooling season']
df['seasons'] = np.select(conditions, choices, default='Heating season')
df

使用 np.where

df['seasons'] = np.where(df.datetime.dt.month.isin(np.arange(5,10)), 'Cooling season','Heating season')
df

输出

    datetime            column1     seasons
0   2021-01-01 01:00:00 11      Heating season
1   2021-05-01 02:00:00 10      Cooling season
2   2021-12-01 03:00:00 1       Heating season
3   2021-11-01 04:00:00 5       Heating season
4   2021-07-01 05:00:00 20      Cooling season

Answer 2

df["seasons"] = np.where((df["datetime"].dt.month >= 5) 
                          & (df["datetime"].dt.month <= 9),
                         "Cooling season", "Heating season")

>>> df
             datetime  column1         seasons
0 2021-01-01 01:00:00       11  Heating season
1 2021-05-05 02:00:00       10  Cooling season
2 2021-12-12 03:00:00        1  Heating season
3 2021-11-11 04:00:00        5  Heating season
4 2021-07-07 05:00:00       20  Cooling season