Python：如何在几天的窗口内按特定日期过滤 Pandas 中日期的 DataFrame？答案

【问题标题】：Python: How to filter a DataFrame of dates in Pandas by a particular date within a window of some days?Python：如何在几天的窗口内按特定日期过滤 Pandas 中日期的 DataFrame？
【发布时间】：2016-10-20 00:23:30
【问题描述】：

我有一个日期数据框，并希望过滤特定日期 +- 某些天。

import pandas as pd
import numpy as np
import datetime

dates = pd.date_range(start="08/01/2009",end="08/01/2012",freq="D")
df = pd.DataFrame(np.random.rand(len(dates), 1)*1500, index=dates, columns=['Power'])

如果我选择让我们说日期2009-08-03 和5 天的窗口，输出将类似于：

>>> 
                  Power
2010-07-29   713.108020
2010-07-30  1055.109543
2010-07-31   951.159099
2010-08-01  1350.638983
2010-08-02   453.166697
2010-08-03  1066.859386
2010-08-04  1381.900717
2010-08-05   107.489179
2010-08-06  1195.945723
2010-08-07  1209.762910
2010-08-08   349.554492

注意：我要解决的原始问题是在Python: Filter DataFrame in Pandas by hour, day and month grouped by year

【问题讨论】：

标签： python date datetime pandas dataframe

【解决方案1】：

我为此创建的函数是filterDaysWindow，可以按如下方式使用：

import pandas as pd
import numpy as np
import datetime

dates = pd.date_range(start="08/01/2009",end="08/01/2012",freq="D")
df = pd.DataFrame(np.random.rand(len(dates), 1)*1500, index=dates, columns=['Power'])

def filterDaysWindow(df, date, daysWindow):
    """
    Filter a Dataframe by a date within a window of days

    @type df: DataFrame
    @param df: DataFrame of dates

    @type date: datetime.date
    @param date: date to focus on

    @type daysWindow: int
    @param daysWindow: Number of days to perform the days window selection

    @rtype: DataFrame
    @return: Returns a DataFrame with dates within date+-daysWindow
    """    
    dateStart = date - datetime.timedelta(days=daysWindow)
    dateEnd = date + datetime.timedelta(days=daysWindow)
    return df [dateStart:dateEnd]

df_filtered = filterDaysWindow(df, datetime.date(2010,8,3), 5)
print df_filtered

【讨论】：