pandas 重新采样时间序列向后计数(或反向重新采样) [英] Pandas resample time series counting backwards (or reverse resample)

问题描述

我想对倒计时的熊猫时间序列重新采样.例如，让我们设置一个简单的11天时间序列:

I want to resample a pandas time series counting backwards. For example, let's set up a simple time series of 11 days:

>>> index = pd.date_range('01-01-2018', '01-11-2018', freq='D')
>>> randint = np.random.randint(low=0, high=9, size=(len(index), 1))

>>> df = pd.DataFrame(randint, index=index, columns=['random'])
>>> print(df)

            random
2018-01-01       8
2018-01-02       8
2018-01-03       1
2018-01-04       4
2018-01-05       3
2018-01-06       5
2018-01-07       2
2018-01-08       6
2018-01-09       5
2018-01-10       1
2018-01-11       3

默认的熊猫行为

如果每隔5天重新采样一次，我会得到:

Default pandas behavior

If I resample it every 5 days, I'd get:

>>> df_5d = df.resample('5D').sum()
>>> print(df_5d)

            random
2018-01-01      24
2018-01-06      19
2018-01-11       3

基本上，您有3个分组:前两个组有5个成员，最后一个组有1个，总共总共11个成员:

Basically you have 3 groupings: the first two groups have 5 members and the last group has 1, for a total of 11 members overall:

Start        End
2018-01-01   2018-01-05
2018-01-06   2018-01-10
2018-01-11   2018-01-11

我想要的是这个

>>> df_5d = df.resample('5D').sum()
>>> print(df_5d)

            random
2018-01-01       8
2018-01-02      21
2018-01-07      17

并且分组如下所示.查看我如何从最近的日期开始倒数'5D':

And the groupings are shown below. See how I counted '5D' backwards starting from the latest date:

Start        End
2018-01-01   2018-01-01
2018-01-02   2018-01-06
2018-01-07   2018-01-11

如何对倒计时的熊猫时间序列重新采样?

How do I resample a pandas time series counting backwards?

推荐答案

一种解决方法是将原始的df一分为二，以便能够使用标准的重采样，然后pd.concat都重新采样数据帧，例如:

A workaround could be to divise your original df in two, to be able to use the standard resampling, then pd.concat both resampled dataframes, such as:

res_interval = 5
df_res = pd.concat([df[:len(df)%res_interval].resample('{}D'.format(res_interval)).sum(),
                    df[len(df)%res_interval:].resample('{}D'.format(res_interval)).sum()])

加上我的随机数，我得到:

and with my random number, I get:

            random
2018-01-01       1
2018-01-02      13
2018-01-07      26

这篇关于 pandas 重新采样时间序列向后计数(或反向重新采样)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！