Python 3.x 将缺少的日期时间插入到数据帧Python中

我有一个数据帧（下面的示例）：

如何填充缺失的值，使数据帧从第一天的12:00:00 AM开始，到最后一天的11:00:00 PM结束，这意味着它将产生如下结果：

    Date        Time        Datetime            Value
0   23/8/2019   12:00:00 AM 2019-08-23 00:00:00 NA
1   23/8/2019    1:00:00 AM 2019-08-23 01:00:00 NA 
                 .
                 .
                 .       
22  23/8/2019    9:00:00 PM 2019-08-23 21:00:00 10
23  23/8/2019   10:00:00 PM 2019-08-23 22:00:00 20
24  23/8/2019   11:00:00 PM 2019-08-23 23:00:00 40
25  24/8/2019   12:00:00 AM 2019-08-24 00:00:00 20
26  24/8/2019    1:00:00 AM 2019-08-24 01:00:00 30
27  24/8/2019    2:00:00 AM 2019-08-24 02:00:00 5
                 .
                 .
                 .
47  24/8/2019   10:00:00 PM 2019-08-24 22:00:00 NA
48  24/8/2019   11:00:00 PM 2019-08-24 23:00:00 NA 

---

首先必须按最小值添加第一个和最后一个日期时间，最大值为

datetime

，删除时间并在中添加

23小时

s，然后按以下方式添加所有介于by、last reasign

Date

和

Time

列之间的日期时间：

---

---

首先必须按最小值添加第一个和最后一个日期时间，最大值为

datetime

，删除时间并在中添加

23小时

s，然后按以下方式添加所有介于by、last reasign

Date

和

Time

列之间的日期时间：

---

    Date        Time        Datetime            Value
0   23/8/2019   12:00:00 AM 2019-08-23 00:00:00 NA
1   23/8/2019    1:00:00 AM 2019-08-23 01:00:00 NA 
                 .
                 .
                 .       
22  23/8/2019    9:00:00 PM 2019-08-23 21:00:00 10
23  23/8/2019   10:00:00 PM 2019-08-23 22:00:00 20
24  23/8/2019   11:00:00 PM 2019-08-23 23:00:00 40
25  24/8/2019   12:00:00 AM 2019-08-24 00:00:00 20
26  24/8/2019    1:00:00 AM 2019-08-24 01:00:00 30
27  24/8/2019    2:00:00 AM 2019-08-24 02:00:00 5
                 .
                 .
                 .
47  24/8/2019   10:00:00 PM 2019-08-24 22:00:00 NA
48  24/8/2019   11:00:00 PM 2019-08-24 23:00:00 NA 

df = pd.DataFrame(list(zip(date,time,datetime,value)), 
                  columns=['Date','Time','Datetime','Value'])

s = df['Datetime'].min().normalize()
e = df['Datetime'].max().normalize() + pd.Timedelta(23, 'H') 

df = df.append(pd.DataFrame({'Datetime':[s, e]}), ignore_index=True).sort_values('Datetime')
df = df.set_index('Datetime').asfreq('H').reset_index()
df['Date'] = df['Datetime'].dt.strftime('%d/%m/%Y')
df['Time'] = df['Datetime'].dt.strftime('%H:%M:%S %p')

print (df)
              Datetime        Date         Time  Value
0  2019-08-23 00:00:00  23/08/2019  00:00:00 AM    NaN
1  2019-08-23 01:00:00  23/08/2019  01:00:00 AM    NaN
2  2019-08-23 02:00:00  23/08/2019  02:00:00 AM    NaN
3  2019-08-23 03:00:00  23/08/2019  03:00:00 AM    NaN
4  2019-08-23 04:00:00  23/08/2019  04:00:00 AM    NaN
5  2019-08-23 05:00:00  23/08/2019  05:00:00 AM    NaN
6  2019-08-23 06:00:00  23/08/2019  06:00:00 AM    NaN
7  2019-08-23 07:00:00  23/08/2019  07:00:00 AM    NaN
8  2019-08-23 08:00:00  23/08/2019  08:00:00 AM    NaN
9  2019-08-23 09:00:00  23/08/2019  09:00:00 AM    NaN
10 2019-08-23 10:00:00  23/08/2019  10:00:00 AM    NaN
11 2019-08-23 11:00:00  23/08/2019  11:00:00 AM    NaN
12 2019-08-23 12:00:00  23/08/2019  12:00:00 PM    NaN
13 2019-08-23 13:00:00  23/08/2019  13:00:00 PM    NaN
14 2019-08-23 14:00:00  23/08/2019  14:00:00 PM    NaN
15 2019-08-23 15:00:00  23/08/2019  15:00:00 PM    NaN
16 2019-08-23 16:00:00  23/08/2019  16:00:00 PM    NaN
17 2019-08-23 17:00:00  23/08/2019  17:00:00 PM    NaN
18 2019-08-23 18:00:00  23/08/2019  18:00:00 PM    NaN
19 2019-08-23 19:00:00  23/08/2019  19:00:00 PM    NaN
20 2019-08-23 20:00:00  23/08/2019  20:00:00 PM    NaN
21 2019-08-23 21:00:00  23/08/2019  21:00:00 PM   10.0
22 2019-08-23 22:00:00  23/08/2019  22:00:00 PM   20.0
23 2019-08-23 23:00:00  23/08/2019  23:00:00 PM   40.0
24 2019-08-24 00:00:00  24/08/2019  00:00:00 AM   20.0
25 2019-08-24 01:00:00  24/08/2019  01:00:00 AM   30.0
26 2019-08-24 02:00:00  24/08/2019  02:00:00 AM    5.0
27 2019-08-24 03:00:00  24/08/2019  03:00:00 AM    NaN
28 2019-08-24 04:00:00  24/08/2019  04:00:00 AM    NaN
29 2019-08-24 05:00:00  24/08/2019  05:00:00 AM    NaN
30 2019-08-24 06:00:00  24/08/2019  06:00:00 AM    NaN
31 2019-08-24 07:00:00  24/08/2019  07:00:00 AM    NaN
32 2019-08-24 08:00:00  24/08/2019  08:00:00 AM    NaN
33 2019-08-24 09:00:00  24/08/2019  09:00:00 AM    NaN
34 2019-08-24 10:00:00  24/08/2019  10:00:00 AM    NaN
35 2019-08-24 11:00:00  24/08/2019  11:00:00 AM    NaN
36 2019-08-24 12:00:00  24/08/2019  12:00:00 PM    NaN
37 2019-08-24 13:00:00  24/08/2019  13:00:00 PM    NaN
38 2019-08-24 14:00:00  24/08/2019  14:00:00 PM    NaN
39 2019-08-24 15:00:00  24/08/2019  15:00:00 PM    NaN
40 2019-08-24 16:00:00  24/08/2019  16:00:00 PM    NaN
41 2019-08-24 17:00:00  24/08/2019  17:00:00 PM    NaN
42 2019-08-24 18:00:00  24/08/2019  18:00:00 PM    NaN
43 2019-08-24 19:00:00  24/08/2019  19:00:00 PM    NaN
44 2019-08-24 20:00:00  24/08/2019  20:00:00 PM    NaN
45 2019-08-24 21:00:00  24/08/2019  21:00:00 PM    NaN
46 2019-08-24 22:00:00  24/08/2019  22:00:00 PM    NaN
47 2019-08-24 23:00:00  24/08/2019  23:00:00 PM    NaN