pandas 将datetimeindex格式转换为四分之一 [英] pandas format datetimeindex to quarters

问题描述

通过重新抽样工作，我将我的每月值转换为季度值:

With a resample job, I have my monthly values converted to quarterly values:

hs=hs.resample('QS',axis=1).mean()

效果很好，我的专栏看起来像这样:

Works well, my columns look like this:

hs.columns:
DatetimeIndex(['2000-01-01', '2000-04-01', '2000-07-01', '2000-10-01',
           '2001-01-01', '2001-04-01', '2001-07-01', '2001-10-01',
           '2002-01-01', '2002-04-01', '2002-07-01', '2002-10-01',

现在，我希望他们将其转换为YYYYq [1-4]格式，我认为该格式应尽可能简单(根据此

Now I want them to convert in the YYYYq[1-4] format, which I thought should be as easy as (according to this Link):

hs.columns.strftime('%Yq%q')

但这给出了:

array(['2000qq', '2000qq', '2000qq', '2000qq', '2001qq', '2001qq',
   '2001qq', '2001qq', '2002qq', '2002qq', '2002qq', '2002qq',
   '2003qq', '2003qq', '2003qq', '2003qq', '2004qq', '2004qq',

我在哪里出错了，我该如何解决?

Where do I go wrong and how can i fix this?

推荐答案

文档在 Period 数据类型而非 Datetime 数据类型上指定了strftime；要使用%q格式程序，可以将datetime索引转换为Period(天数为单位)，然后对其进行格式化:

The documentation specifies strftime on Period data type not Datetime data type; To use %q formatter, you can convert the datetime Index to Period (days as unit) and then format it:

cols = pd.DatetimeIndex(['2000-01-01', '2000-04-01', '2000-07-01', '2000-10-01',
                         '2001-01-01', '2001-04-01', '2001-07-01', '2001-10-01',
                         '2002-01-01', '2002-04-01', '2002-07-01', '2002-10-01'])

cols.to_period('D').strftime('%Yq%q')
# hs.columns.to_period('D').strftime('%Yq%q')
#array([u'2000q1', u'2000q2', u'2000q3', u'2000q4', u'2001q1', u'2001q2',
#       u'2001q3', u'2001q4', u'2002q1', u'2002q2', u'2002q3', u'2002q4'],
#      dtype='<U6')

或者仅将to_period与Q(四分之一)作为单位使用:

Or simply use to_period with Q (quarter) as unit:

cols.to_period('Q')
# hs.columns.to_period('Q')
#PeriodIndex(['2000Q1', '2000Q2', '2000Q3', '2000Q4', '2001Q1', '2001Q2',
#             '2001Q3', '2001Q4', '2002Q1', '2002Q2', '2002Q3', '2002Q4'],
#            dtype='period[Q-DEC]', freq='Q-DEC')

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