DOC: Add reference to frequency strings

 - [x] closes #13160

Author: Sahil Dua <[email protected]>

This patch had conflicts when merged, resolved by
Committer: Joris Van den Bossche <[email protected]>

Closes #13632 from sahildua2305/frequency-strings-fix and squashes the following commits:

b45ae21 [Sahil Dua] DOC: Add learn more text in generic and removed from window
fff5da7 [Sahil Dua] Fix links and text for reference
7b7045a [Sahil Dua] DOC: Add reference to frequency strings in docs
02c44bb [Sahil Dua] Add reference to frequency strings; fixes #13160

Author: sahildua2305

doc/source/timeseries.rst

@@ -567,11 +567,11 @@ DateOffset objects
 ------------------
 
 In the preceding examples, we created DatetimeIndex objects at various
-frequencies by passing in frequency strings like 'M', 'W', and 'BM to the
-``freq`` keyword. Under the hood, these frequency strings are being translated
-into an instance of pandas ``DateOffset``, which represents a regular
-frequency increment. Specific offset logic like "month", "business day", or
-"one hour" is represented in its various subclasses.
+frequencies by passing in :ref:`frequency strings <timeseries.offset_aliases>`
+like 'M', 'W', and 'BM to the ``freq`` keyword. Under the hood, these frequency
+strings are being translated into an instance of pandas ``DateOffset``,
+which represents a regular frequency increment. Specific offset logic like
+"month", "business day", or "one hour" is represented in its various subclasses.
 
 .. csv-table::
     :header: "Class name", "Description"
@@ -953,7 +953,7 @@ You can use keyword arguments suported by either ``BusinessHour`` and ``CustomBu
     # Monday is skipped because it's a holiday, business hour starts from 10:00
     dt + bhour_mon * 2
 
-.. _timeseries.alias:
+.. _timeseries.offset_aliases:
 
 Offset Aliases
 ~~~~~~~~~~~~~~

doc/source/whatsnew/v0.19.0.txt

@@ -622,7 +622,7 @@ Removal of prior version deprecations/changes
      pandas/tseries/frequencies.py:465: FutureWarning: Freq "W@MON" is deprecated, use "W-MON" as alternative.
      Out[2]: DatetimeIndex(['2016-07-04', '2016-07-11', '2016-07-18'], dtype='datetime64[ns]', freq='W-MON')
 
-  Now legacy time rules raises ``ValueError``. For the list of currently supported offsets, see :ref:`here <timeseries.alias>`
+  Now legacy time rules raises ``ValueError``. For the list of currently supported offsets, see :ref:`here <timeseries.offset_aliases>`
 
 - The ``tquery`` and ``uquery`` functions in the ``pandas.io.sql`` module are removed (:issue:`5950`).
 

pandas/core/generic.py

@@ -3982,6 +3982,9 @@ def asfreq(self, freq, method=None, how=None, normalize=False):
         Returns
         -------
         converted : type of caller
+
+        To learn more about the frequency strings, please see `this link
+        <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
         """
         from pandas.tseries.resample import asfreq
         return asfreq(self, freq, method=method, how=how, normalize=normalize)
@@ -4053,6 +4056,9 @@ def resample(self, rule, how=None, axis=0, fill_method=None, closed=None,
             range from 0 through 4. Defaults to 0
 
 
+        To learn more about the offset strings, please see `this link
+        <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
+
         Examples
         --------
 

pandas/stats/moments.py

@@ -271,6 +271,9 @@ def rolling_count(arg, window, **kwargs):
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('rolling', 'count', arg, window=window, **kwargs)
 
@@ -521,6 +524,9 @@ def rolling_quantile(arg, window, quantile, min_periods=None, freq=None,
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('rolling',
                          'quantile',
@@ -570,6 +576,9 @@ def rolling_apply(arg, window, func, min_periods=None, freq=None,
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('rolling',
                          'apply',
@@ -642,6 +651,9 @@ def rolling_window(arg, window=None, win_type=None, min_periods=None,
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     func = 'mean' if mean else 'sum'
     return ensure_compat('rolling',
@@ -707,6 +719,9 @@ def expanding_count(arg, freq=None):
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('expanding', 'count', arg, freq=freq)
 
@@ -735,6 +750,9 @@ def expanding_quantile(arg, quantile, min_periods=1, freq=None):
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('expanding',
                          'quantile',
@@ -818,6 +836,9 @@ def expanding_apply(arg, func, min_periods=1, freq=None,
     The `freq` keyword is used to conform time series data to a specified
     frequency by resampling the data. This is done with the default parameters
     of :meth:`~pandas.Series.resample` (i.e. using the `mean`).
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return ensure_compat('expanding',
                          'apply',

pandas/tseries/index.py

@@ -189,6 +189,9 @@ class DatetimeIndex(DatelikeOps, TimelikeOps, DatetimeIndexOpsMixin,
         Attempt to infer fall dst-transition hours based on order
     name : object
         Name to be stored in the index
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
 
     _typ = 'datetimeindex'
@@ -2026,6 +2029,9 @@ def date_range(start=None, end=None, periods=None, freq='D', tz=None,
     -----
     2 of start, end, or periods must be specified
 
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
+
     Returns
     -------
     rng : DatetimeIndex
@@ -2066,6 +2072,9 @@ def bdate_range(start=None, end=None, periods=None, freq='B', tz=None,
     -----
     2 of start, end, or periods must be specified
 
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
+
     Returns
     -------
     rng : DatetimeIndex
@@ -2117,6 +2126,9 @@ def cdate_range(start=None, end=None, periods=None, freq='C', tz=None,
     -----
     2 of start, end, or periods must be specified
 
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
+
     Returns
     -------
     rng : DatetimeIndex

pandas/tseries/tdi.py

@@ -110,6 +110,9 @@ class TimedeltaIndex(DatetimeIndexOpsMixin, TimelikeOps, Int64Index):
         the 'left', 'right', or both sides (None)
     name : object
         Name to be stored in the index
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
 
     _typ = 'timedeltaindex'
@@ -1014,6 +1017,9 @@ def timedelta_range(start=None, end=None, periods=None, freq='D',
     Returns
     -------
     rng : TimedeltaIndex
+
+    To learn more about the frequency strings, please see `this link
+    <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
     """
     return TimedeltaIndex(start=start, end=end, periods=periods,
                           freq=freq, name=name,