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DOC: Add more documentation showcasing CalendarDay #22633

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c580fc3
DOC: Add more docs about CalendarDay
Sep 8, 2018
f131230
change class to func
Sep 8, 2018
3da2c7d
add missing index
Sep 8, 2018
f0761c3
Merge remote-tracking branch 'upstream/master' into document_calendar…
Sep 13, 2018
3b8c102
Add more calendardaytests
Sep 13, 2018
12b4694
Merge remote-tracking branch 'upstream/master' into document_calendar…
Sep 13, 2018
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19 changes: 19 additions & 0 deletions doc/source/timeseries.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -900,12 +900,31 @@ calendar time arithmetic. :class:`CalendarDay` is useful preserving calendar day
semantics with date times with have day light savings transitions, i.e. :class:`CalendarDay`
will preserve the hour before the day light savings transition.

Addition with :class:`CalendarDay`:

.. ipython:: python

ts = pd.Timestamp('2016-10-30 00:00:00', tz='Europe/Helsinki')
ts + pd.offsets.Day(1)
ts + pd.offsets.CalendarDay(1)

Creating a :func:`date_range`:

.. ipython:: python

start = pd.Timestamp('2016-10-30 00:00:00', tz='Europe/Helsinki')
pd.date_range(start, freq='D', periods=3)
pd.date_range(start, freq='CD', periods=3)

Resampling a timeseries:

.. ipython:: python

idx = pd.date_range("2016-10-30", freq='H', periods=4*24, tz='Europe/Helsinki')
s = pd.Series(range(len(idx)), index=idx)
s.resample('D').count()
s.resample('CD').count()
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Is this supposed to work on master? After a clean build locally I get a ValueError: Invalid frequency: CD.

Don't think doctest covers these files; if it does then my mistake but figured it was worth asking

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This currently works on master:

In [3]: pd.__version__
Out[3]: '0.24.0.dev0+563.g0976e1261'

In [4]:    idx = pd.date_range("2016-10-30", freq='H', periods=4*24, tz='Europe/
   ...: Helsinki')
   ...:    s = pd.Series(range(len(idx)), index=idx)
   ...:    s.resample('D').count()
   ...:    s.resample('CD').count()
   ...:
   ...:
Out[4]:
2016-10-30 00:00:00+03:00    25
2016-10-31 00:00:00+02:00    24
2016-11-01 00:00:00+02:00    24
2016-11-02 00:00:00+02:00    23
Freq: CD, dtype: int64

I am not sure if the doctest uses master or the the latest tagged branch.



Parametric Offsets
~~~~~~~~~~~~~~~~~~
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22 changes: 21 additions & 1 deletion doc/source/whatsnew/v0.24.0.txt
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Expand Up @@ -317,14 +317,34 @@ and respect calendar day arithmetic while :class:`Day` and frequency alias ``'D'
will now respect absolute time (:issue:`22274`, :issue:`20596`, :issue:`16980`, :issue:`8774`)
See the :ref:`documentation here <timeseries.dayvscalendarday>` for more information.

Addition with :class:`CalendarDay` across a daylight savings time transition:
The difference between :class:`Day` vs :class:`CalendarDay` is most apparent
with timezone-aware datetime data with a daylight savings time transition:
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You say "most apparent with timezone-aware data". But is there a case where this is actually relevant for tz naive data?

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There is no difference between Day and CalendarDay for tz naive data. I've parameterized some tz naive data tests for 'D' and 'CD' to ensure this behavior.


Addition with :class:`CalendarDay`:

.. ipython:: python

ts = pd.Timestamp('2016-10-30 00:00:00', tz='Europe/Helsinki')
ts + pd.offsets.Day(1)
ts + pd.offsets.CalendarDay(1)

Creating a :func:`date_range`:

.. ipython:: python

start = pd.Timestamp('2016-10-30 00:00:00', tz='Europe/Helsinki')
pd.date_range(start, freq='D', periods=3)
pd.date_range(start, freq='CD', periods=3)

Resampling a timeseries:

.. ipython:: python

idx = pd.date_range("2016-10-30", freq='H', periods=4*24, tz='Europe/Helsinki')
s = pd.Series(range(len(idx)), index=idx)
s.resample('D').count()
s.resample('CD').count()

.. _whatsnew_0240.api_breaking.period_end_time:

Time values in ``dt.end_time`` and ``to_timestamp(how='end')``
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