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CLN: Refactor string special methods #4092
| @@ -8,13 +8,13 @@ enhancements along with a large number of bug fixes. | ||
| Highlites include a consistent I/O API naming scheme, routines to read html, | ||
| write multi-indexes to csv files, read & write STATA data files, read & write JSON format | ||
| -files, Python 3 support for ``HDFStore``, filtering of groupby expressions via ``filter``, and a | ||
| +files, Python 3 support for ``HDFStore``, filtering of groupby expressions via ``filter``, and a | ||
cpcloud
Member
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| revamped ``replace`` routine that accepts regular expressions. | ||
| API changes | ||
| ~~~~~~~~~~~ | ||
| - - The I/O API is now much more consistent with a set of top level ``reader`` functions | ||
| + - The I/O API is now much more consistent with a set of top level ``reader`` functions | ||
| accessed like ``pd.read_csv()`` that generally return a ``pandas`` object. | ||
| * ``read_csv`` | ||
| @@ -38,7 +38,7 @@ API changes | ||
| * ``to_clipboard`` | ||
| - - Fix modulo and integer division on Series,DataFrames to act similary to ``float`` dtypes to return | ||
| + - Fix modulo and integer division on Series,DataFrames to act similary to ``float`` dtypes to return | ||
| ``np.nan`` or ``np.inf`` as appropriate (:issue:`3590`). This correct a numpy bug that treats ``integer`` | ||
| and ``float`` dtypes differently. | ||
| @@ -50,15 +50,15 @@ API changes | ||
| p / p | ||
| p / 0 | ||
| - - Add ``squeeze`` keyword to ``groupby`` to allow reduction from | ||
| + - Add ``squeeze`` keyword to ``groupby`` to allow reduction from | ||
| DataFrame -> Series if groups are unique. This is a Regression from 0.10.1. | ||
| - We are reverting back to the prior behavior. This means groupby will return the | ||
| - same shaped objects whether the groups are unique or not. Revert this issue (:issue:`2893`) | ||
| + We are reverting back to the prior behavior. This means groupby will return the | ||
| + same shaped objects whether the groups are unique or not. Revert this issue (:issue:`2893`) | ||
| with (:issue:`3596`). | ||
| .. ipython:: python | ||
| - df2 = DataFrame([{"val1": 1, "val2" : 20}, {"val1":1, "val2": 19}, | ||
| + df2 = DataFrame([{"val1": 1, "val2" : 20}, {"val1":1, "val2": 19}, | ||
| {"val1":1, "val2": 27}, {"val1":1, "val2": 12}]) | ||
| def func(dataf): | ||
| return dataf["val2"] - dataf["val2"].mean() | ||
| @@ -96,9 +96,9 @@ API changes | ||
| and thus you should cast to an appropriate numeric dtype if you need to | ||
| plot something. | ||
| - - Add ``colormap`` keyword to DataFrame plotting methods. Accepts either a | ||
| - matplotlib colormap object (ie, matplotlib.cm.jet) or a string name of such | ||
| - an object (ie, 'jet'). The colormap is sampled to select the color for each | ||
| + - Add ``colormap`` keyword to DataFrame plotting methods. Accepts either a | ||
| + matplotlib colormap object (ie, matplotlib.cm.jet) or a string name of such | ||
| + an object (ie, 'jet'). The colormap is sampled to select the color for each | ||
| column. Please see :ref:`visualization.colormaps` for more information. | ||
| (:issue:`3860`) | ||
| @@ -159,6 +159,18 @@ API changes | ||
| ``bs4`` + ``html5lib`` when lxml fails to parse. a list of parsers to try | ||
| until success is also valid | ||
| + - The internal ``pandas`` class hierarchy has changed (slightly). The | ||
| + previous ``PandasObject`` now is called ``PandasContainer`` and a new | ||
| + ``PandasObject`` has become the baseclass for ``PandasContainer`` as well | ||
| + as ``Index``, ``Categorical``, ``GroupBy``, ``SparseList``, and | ||
| + ``SparseArray`` (+ their base classes). Currently, ``PandasObject`` | ||
| + provides string methods (from ``StringMixin``). (:issue:`4090`, :issue:`4092`) | ||
| + | ||
| + - New ``StringMixin`` that, given a ``__unicode__`` method, gets python 2 and | ||
| + python 3 compatible string methods (``__str__``, ``__bytes__``, and | ||
| + ``__repr__``). Plus string safety throughout. Now employed in many places | ||
| + throughout the pandas library. (:issue:`4090`, :issue:`4092`) | ||
| + | ||
| I/O Enhancements | ||
| ~~~~~~~~~~~~~~~~ | ||
| @@ -184,7 +196,7 @@ I/O Enhancements | ||
| .. warning:: | ||
| - You may have to install an older version of BeautifulSoup4, | ||
| + You may have to install an older version of BeautifulSoup4, | ||
| :ref:`See the installation docs<install.optional_dependencies>` | ||
| - Added module for reading and writing Stata files: ``pandas.io.stata`` (:issue:`1512`) | ||
| @@ -203,15 +215,15 @@ I/O Enhancements | ||
| - The option, ``tupleize_cols`` can now be specified in both ``to_csv`` and | ||
| ``read_csv``, to provide compatiblity for the pre 0.12 behavior of | ||
| writing and reading multi-index columns via a list of tuples. The default in | ||
| - 0.12 is to write lists of tuples and *not* interpret list of tuples as a | ||
| - multi-index column. | ||
| + 0.12 is to write lists of tuples and *not* interpret list of tuples as a | ||
| + multi-index column. | ||
| Note: The default behavior in 0.12 remains unchanged, but starting with 0.13, | ||
| - the default *to* write and read multi-index columns will be in the new | ||
| + the default *to* write and read multi-index columns will be in the new | ||
| format. (:issue:`3571`, :issue:`1651`, :issue:`3141`) | ||
| - If an ``index_col`` is not specified (e.g. you don't have an index, or wrote it | ||
| - with ``df.to_csv(..., index=False``), then any ``names`` on the columns index will | ||
| + with ``df.to_csv(..., index=False``), then any ``names`` on the columns index will | ||
| be *lost*. | ||
| .. ipython:: python | ||
| @@ -296,8 +308,8 @@ Other Enhancements | ||
| pd.get_option('a.b') | ||
| pd.get_option('b.c') | ||
| - - The ``filter`` method for group objects returns a subset of the original | ||
| - object. Suppose we want to take only elements that belong to groups with a | ||
| + - The ``filter`` method for group objects returns a subset of the original | ||
| + object. Suppose we want to take only elements that belong to groups with a | ||
| group sum greater than 2. | ||
| .. ipython:: python | ||
| @@ -317,7 +329,7 @@ Other Enhancements | ||
| dff.groupby('B').filter(lambda x: len(x) > 2) | ||
| Alternatively, instead of dropping the offending groups, we can return a | ||
| - like-indexed objects where the groups that do not pass the filter are | ||
| + like-indexed objects where the groups that do not pass the filter are | ||
| filled with NaNs. | ||
| .. ipython:: python | ||
| @@ -333,9 +345,9 @@ Experimental Features | ||
| - Added experimental ``CustomBusinessDay`` class to support ``DateOffsets`` | ||
| with custom holiday calendars and custom weekmasks. (:issue:`2301`) | ||
| - | ||
| + | ||
| .. note:: | ||
| - | ||
| + | ||
| This uses the ``numpy.busdaycalendar`` API introduced in Numpy 1.7 and | ||
| therefore requires Numpy 1.7.0 or newer. | ||
| @@ -416,7 +428,7 @@ Bug Fixes | ||
| - Extend ``reindex`` to correctly deal with non-unique indices (:issue:`3679`) | ||
| - ``DataFrame.itertuples()`` now works with frames with duplicate column | ||
| names (:issue:`3873`) | ||
| - - Bug in non-unique indexing via ``iloc`` (:issue:`4017`); added ``takeable`` argument to | ||
| + - Bug in non-unique indexing via ``iloc`` (:issue:`4017`); added ``takeable`` argument to | ||
| ``reindex`` for location-based taking | ||
| - ``DataFrame.from_records`` did not accept empty recarrays (:issue:`3682`) | ||
| @@ -0,0 +1,58 @@ | ||
| +""" | ||
| +Base class(es) for all pandas objects. | ||
| +""" | ||
| +from pandas.util import py3compat | ||
| + | ||
| +class StringMixin(object): | ||
| + """implements string methods so long as object defines a `__unicode__` method. | ||
| + Handles Python2/3 compatibility transparently.""" | ||
| + # side note - this could be made into a metaclass if more than one object nees | ||
| + def __str__(self): | ||
| + """ | ||
| + Return a string representation for a particular object. | ||
| + | ||
| + Invoked by str(obj) in both py2/py3. | ||
| + Yields Bytestring in Py2, Unicode String in py3. | ||
| + """ | ||
| + | ||
| + if py3compat.PY3: | ||
| + return self.__unicode__() | ||
| + return self.__bytes__() | ||
| + | ||
| + def __bytes__(self): | ||
| + """ | ||
| + Return a string representation for a particular object. | ||
| + | ||
| + Invoked by bytes(obj) in py3 only. | ||
| + Yields a bytestring in both py2/py3. | ||
| + """ | ||
| + from pandas.core.config import get_option | ||
| + | ||
| + encoding = get_option("display.encoding") | ||
| + return self.__unicode__().encode(encoding, 'replace') | ||
| + | ||
| + def __repr__(self): | ||
| + """ | ||
| + Return a string representation for a particular object. | ||
| + | ||
| + Yields Bytestring in Py2, Unicode String in py3. | ||
| + """ | ||
| + return str(self) | ||
| + | ||
| +class PandasObject(StringMixin): | ||
| + """baseclass for various pandas objects""" | ||
| + | ||
| + @property | ||
| + def _constructor(self): | ||
| + """class constructor (for this class it's just `__class__`""" | ||
| + return self.__class__ | ||
| + | ||
| + def __unicode__(self): | ||
| + """ | ||
| + Return a string representation for a particular object. | ||
| + | ||
| + Invoked by unicode(obj) in py2 only. Yields a Unicode String in both | ||
| + py2/py3. | ||
| + """ | ||
| + # Should be overwritten by base classes | ||
| + return object.__repr__(self) | ||
jtratner
Contributor
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Oops, something went wrong.
@cpcloud is it worth it to fix the trailing whitespace? Easy to remove the fix, but it was bothering me a little.