pandas 重新采样到季度，并显示开始和结束月份 [英] Pandas resample to quarterly with showing start and end month

问题描述

我的df看起来像这样:

My df looks like this:

            Total
language    Julia   Python  R   SQLite
date                
2015-03-01  NaN NaN 17.0    NaN
2015-04-01  NaN 156.0   189.0   NaN
2015-05-01  13.0    212.0   202.0   NaN

该指数是按月计算，我希望它是每季度一次:

The index is on a monthly basis and I want it to be quarterly:

df.resample("Q").sum()

给我这个:

            Total
language    Julia   Python  R   SQLite
date                
2015-03-31  NaN NaN 17.0    NaN
2015-06-30  22.0    677.0   594.0   26.0
2015-09-30  37.0    1410.0  1250.0  146.0

但是我想显示这样的索引，而不是结束日期.所需的df:

But I would like to show the index like this Start month - End month 2017 instead of the end date. Desired df:

                Total
language        Julia   Python  R   SQLite
Jan - Mar, 2015 NaN NaN 17.0    NaN
Apr - Jun, 2015 22.0    677.0   594.0   26.0
Jul - Sep, 2015 37.0    1410.0  1250.0  146.0

有没有做到这一点的大熊猫方法?我是这样做的，但是它很脏，我敢肯定有更好的方法可以做到(示例中缺少docs中的resample方法...):

Is there a pandas way of doing it? I did it like this but it is quite dirty and I am sure there is a better way to do it (the resample method in docs is lacking in examples...):

def quarterlyMonthNmaes(x): 
    start_date = x.name - pd.offsets.MonthBegin(3)
    final_date = str(start_date.strftime('%b')) + " - " + str(x.name.strftime('%b, %Y'))
    return final_date
df["Total"].apply(quarterlyMonthNmaes, axis=1) 

推荐答案

使用或更简单:

idx2 = df.index.strftime('%b %Y')
idx1 = (df.index - pd.offsets.MonthBegin(3)).strftime('%b')
df.index = ['{0[0]}-{0[1]}'.format(x) for x in zip(idx1, idx2)]

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