如何对每列应用不同功能的数据框进行重新采样? [英] How to resample a dataframe with different functions applied to each column?

问题描述

我对熊猫dataframe中的温度和辐射有时间序列.时间分辨率是固定的1分钟.

I have a times series with temperature and radiation in a pandas dataframe. The time resolution is 1 minute in regular steps.

import datetime
import pandas as pd
import numpy as np

date_times = pd.date_range(datetime.datetime(2012, 4, 5, 8, 0),
                           datetime.datetime(2012, 4, 5, 12, 0),
                           freq='1min')
tamb = np.random.sample(date_times.size) * 10.0
radiation = np.random.sample(date_times.size) * 10.0
frame = pd.DataFrame(data={'tamb': tamb, 'radiation': radiation},
                     index=date_times)
frame
<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 241 entries, 2012-04-05 08:00:00 to 2012-04-05 12:00:00
Freq: T
Data columns:
radiation    241  non-null values
tamb         241  non-null values
dtypes: float64(2)

我如何才能将此dataframe降采样为一小时的分辨率，并计算温度的每小时平均值和辐射的每小时总和?

How can I down-sample this dataframe to a resolution of one hour, computing the hourly mean for the temperature and the hourly sum for radiation?

推荐答案

使用pandas 0.18更改了重采样API(请参见

With pandas 0.18 the resample API changed (see the docs). So for pandas >= 0.18 the answer is:

In [31]: frame.resample('1H').agg({'radiation': np.sum, 'tamb': np.mean})
Out[31]: 
                         tamb   radiation
2012-04-05 08:00:00  5.161235  279.507182
2012-04-05 09:00:00  4.968145  290.941073
2012-04-05 10:00:00  4.478531  317.678285
2012-04-05 11:00:00  4.706206  335.258633
2012-04-05 12:00:00  2.457873    8.655838

---

旧答案:

---

Old Answer:

我正在回答我的问题，以反映pandas >= 0.8中与时间序列相关的变化(所有其他答案均已过时).

I am answering my question to reflect the time series related changes in pandas >= 0.8 (all other answers are outdated).

使用大熊猫> = 0.8，答案是:

Using pandas >= 0.8 the answer is:

In [30]: frame.resample('1H', how={'radiation': np.sum, 'tamb': np.mean})
Out[30]: 
                         tamb   radiation
2012-04-05 08:00:00  5.161235  279.507182
2012-04-05 09:00:00  4.968145  290.941073
2012-04-05 10:00:00  4.478531  317.678285
2012-04-05 11:00:00  4.706206  335.258633
2012-04-05 12:00:00  2.457873    8.655838

这篇关于如何对每列应用不同功能的数据框进行重新采样?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！