如何遍历日期列并根据特定条件分配值？

Question

我有一个df如下

       dates       winter   summer  rest  Final
2020-01-01 00:15:00 65.5    71.5    73.0   NaN
2020-01-01 00:30:00 62.6    69.0    70.1   NaN
2020-01-01 00:45:00 59.6    66.3    67.1   NaN
2020-01-01 01:00:00 57.0    63.5    64.5   NaN
2020-01-01 01:15:00 54.8    60.9    62.3   NaN
2020-01-01 01:30:00 53.1    58.6    60.6   NaN
2020-01-01 01:45:00 51.7    56.6    59.2   NaN
2020-01-01 02:00:00 50.5    55.1    57.9   NaN
2020-01-01 02:15:00 49.4    54.2    56.7   NaN
2020-01-01 02:30:00 48.5    53.7    55.6   NaN
2020-01-01 02:45:00 47.9    53.4    54.7   NaN
2020-01-01 03:00:00 47.7    53.3    54.2   NaN
2020-01-01 03:15:00 47.9    53.1    54.1   NaN
2020-01-01 03:30:00 48.7    53.2    54.6   NaN
2020-01-01 03:45:00 50.2    54.1    55.8   NaN
2020-01-01 04:00:00 52.3    56.1    57.9   NaN
2020-04-28 12:30:00 225.1   200.0   209.8  NaN
2020-04-28 12:45:00 215.7   193.8   201.9  NaN
2020-04-28 13:00:00 205.6   186.9   193.4  NaN
2020-04-28 13:15:00 195.7   179.9   185.0  NaN
2020-04-28 13:30:00 186.7   173.4   177.4  NaN
2020-04-28 13:45:00 179.2   168.1   170.9  NaN
2020-04-28 14:00:00 173.8   164.4   166.3  NaN
2020-04-28 14:15:00 171.0   163.0   163.9  NaN
2020-04-28 14:30:00 170.7   163.5   163.6  NaN
2020-12-31 21:15:00 88.5    90.2    89.2   NaN
2020-12-31 21:30:00 85.2    88.5    87.2   NaN
2020-12-31 21:45:00 82.1    86.3    85.0   NaN
2020-12-31 22:00:00 79.4    84.1    83.2   NaN
2020-12-31 22:15:00 77.6    82.4    82.1   NaN
2020-12-31 22:30:00 76.4    81.2    81.7   NaN
2020-12-31 22:45:00 75.6    80.3    81.6   NaN
2020-12-31 23:00:00 74.7    79.4    81.3   NaN
2020-12-31 23:15:00 73.7    78.4    80.6   NaN
2020-12-31 23:30:00 72.3    77.2    79.5   NaN
2020-12-31 23:45:00 70.5    75.7    77.9   NaN
2021-01-01 00:00:00 68.2    73.8    75.7   NaN

dates 列的日期从 2020-01-01 00:15:00 到 2021-01-01 00:00:00 每 15 分钟拆分一次。

我还有以下日期范围条件：

冬季： 01.11 - 20.03

夏季： 15.05 - 14.09

休息： 21.03 - 14.05 & 15.09 - 31.10

我想要做的是创建一个名为season 的新列，它检查dates 列中的每个日期，如果日期在冬季范围内，则分配冬季，如果在夏季范围内，则分配夏季，如果是休息是余数范围。

然后，根据season 列中的值，必须填充Final 列。如果season 列中的值是'winter'，则必须放置winter 列中的值，如果season 列中的值是'summer'，则必须放置summer 列中的值并且以此类推。

如何做到这一点？

Answer 1

想法是标准化同一年的日期时间，然后按Series.between 过滤并通过numpy.select 设置新列：

d = pd.to_datetime(df['dates'].dt.strftime('%m-%d-2020'))

m1 = d.between('2020-11-01','2020-12-31') | d.between('2020-01-01','2020-03-20')
m2 = d.between('2020-05-15','2020-09-14') 

df['Final'] = np.select([m1, m2], ['Winter','Summer'], default='Rest')
print (df)
                dates  winter  summer  rest   Final
0 2020-01-01 00:15:00    65.5    71.5  73.0  Winter
1 2020-06-15 00:30:00    62.6    69.0  70.1  Summer
2 2020-12-25 00:45:00    59.6    66.3  67.1  Winter
3 2020-10-10 01:00:00    57.0    63.5  64.5    Rest