Python:如何在Pandas中按某天窗口内的特定日期筛选日期DataFrame

Question

我有一个日期DataFrame，我想过滤一个特定的日期+-一些天。

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'])

如果我选择日期2009-08-03和5天窗口，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::我想要完成的原始问题是在Python下:按小时，日和月按年分组过滤Pandas中的数据框

Answer 1

我创建的函数是filterDaysWindow，可以如下使用:

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