我有一个带有时间索引的数据帧.每年8月都有一段时间(周期)开始.我想计算每个月的价值与前一年8月(期初)的价值之间的差额. 这样做的目的是为了了解在每个周期中这些值发生了多少变化.
以下是数据的一个小示例:
import pandas as pd
import numpy as np
df = pd.DataFrame({'date': ['2022-01-01 00:00:00', '2022-02-01 00:00:00',
'2021-03-01 00:00:00', '2021-04-01 00:00:00',
'2021-05-01 00:00:00', '2021-06-01 00:00:00',
'2021-07-01 00:00:00', '2021-08-01 00:00:00',
'2021-09-01 00:00:00', '2021-10-01 00:00:00',
'2021-11-01 00:00:00', '2021-12-01 00:00:00',
'2022-01-01 00:00:00', '2022-02-01 00:00:00',
'2022-03-01 00:00:00', '2022-04-01 00:00:00',
'2022-05-01 00:00:00', '2022-06-01 00:00:00',
'2022-07-01 00:00:00', '2022-08-01 00:00:00',
'2022-09-01 00:00:00', '2022-10-01 00:00:00',
'2022-11-01 00:00:00', '2023-12-01 00:00:00',
'2023-01-01 00:00:00', '2023-02-01 00:00:00',
'2023-03-01 00:00:00', '2023-04-01 00:00:00',
'2023-05-01 00:00:00', '2023-06-01 00:00:00',
],
'value1': [0.452762281,0.372262281,0.513928948,0.447762281,
0.377095615,0.355095615,0.271428948,0.291762281,
0.476762281,0.335928948,0.280428948,0.283762281,
0.322928948,0.287262281,0.316928948,0.209262281,
0.407928948,0.254262281,0.232095615,0.264262281,
0.076095615,-0.025237719,-0.042237719,-0.094904385,
0.017428948,-0.036071052,-0.094071052,-0.071404385,
0.008095615,-0.141571052],
'value2': [9.6,8,8.4,6.2,6.2,6,3.9,8.5,8.3,5.3,5.6,5.3,
6.2,6.3,6.9,4.8,6.7,3.6,3,4.6,2.3,1.3,1,0.3,
1.6,0.4,1.5,1.4,2.2,1.2]})
df = df.set_index('date')
我曾try 获得具有相同 struct 的数据帧，但所有值都具有相应8月的值，然后我只需要从一个数据帧中减go 另一个数据帧. 但我也找不到办法go 做.
谢谢你提前了很多.