CLN: reorg groupby to multiple modules (pandas-dev#21820)

pandas/core/api.py

@@ -7,7 +7,7 @@
 from pandas.core.algorithms import factorize, unique, value_counts
 from pandas.core.dtypes.missing import isna, isnull, notna, notnull
 from pandas.core.arrays import Categorical
-from pandas.core.groupby.groupby import Grouper
+from pandas.core.groupby import Grouper
 from pandas.io.formats.format import set_eng_float_format
 from pandas.core.index import (Index, CategoricalIndex, Int64Index,
                                UInt64Index, RangeIndex, Float64Index,

pandas/core/base.py

@@ -648,53 +648,6 @@ def _is_builtin_func(self, arg):
         return self._builtin_table.get(arg, arg)
 
 
-class GroupByMixin(object):
-    """ provide the groupby facilities to the mixed object """
-
-    @staticmethod
-    def _dispatch(name, *args, **kwargs):
-        """ dispatch to apply """
-
-        def outer(self, *args, **kwargs):
-            def f(x):
-                x = self._shallow_copy(x, groupby=self._groupby)
-                return getattr(x, name)(*args, **kwargs)
-            return self._groupby.apply(f)
-        outer.__name__ = name
-        return outer
-
-    def _gotitem(self, key, ndim, subset=None):
-        """
-        sub-classes to define
-        return a sliced object
-
-        Parameters
-        ----------
-        key : string / list of selections
-        ndim : 1,2
-            requested ndim of result
-        subset : object, default None
-            subset to act on
-        """
-        # create a new object to prevent aliasing
-        if subset is None:
-            subset = self.obj
-
-        # we need to make a shallow copy of ourselves
-        # with the same groupby
-        kwargs = dict([(attr, getattr(self, attr))
-                       for attr in self._attributes])
-        self = self.__class__(subset,
-                              groupby=self._groupby[key],
-                              parent=self,
-                              **kwargs)
-        self._reset_cache()
-        if subset.ndim == 2:
-            if is_scalar(key) and key in subset or is_list_like(key):
-                self._selection = key
-        return self
-
-
 class IndexOpsMixin(object):
     """ common ops mixin to support a unified interface / docs for Series /
     Index

pandas/core/groupby/__init__.py

@@ -1,4 +1,4 @@
-# flake8: noqa
-from pandas.core.groupby.groupby import (
-    Grouper, GroupBy, SeriesGroupBy, DataFrameGroupBy
-)
+from pandas.core.groupby.groupby import GroupBy  # flake8: noqa
+from pandas.core.groupby.generic import (
+    SeriesGroupBy, DataFrameGroupBy, PanelGroupBy)  # flake8: noqa
+from pandas.core.groupby.grouper import Grouper  # flake8: noqa

pandas/core/groupby/base.py

@@ -0,0 +1,160 @@
+"""
+Provide basic components for groupby. These defintiions
+hold the whitelist of methods that are exposed on the
+SeriesGroupBy and the DataFrameGroupBy objects.
+"""
+
+import types
+from pandas.util._decorators import make_signature
+from pandas.core.dtypes.common import is_scalar, is_list_like
+
+
+class GroupByMixin(object):
+    """ provide the groupby facilities to the mixed object """
+
+    @staticmethod
+    def _dispatch(name, *args, **kwargs):
+        """ dispatch to apply """
+
+        def outer(self, *args, **kwargs):
+            def f(x):
+                x = self._shallow_copy(x, groupby=self._groupby)
+                return getattr(x, name)(*args, **kwargs)
+            return self._groupby.apply(f)
+        outer.__name__ = name
+        return outer
+
+    def _gotitem(self, key, ndim, subset=None):
+        """
+        sub-classes to define
+        return a sliced object
+
+        Parameters
+        ----------
+        key : string / list of selections
+        ndim : 1,2
+            requested ndim of result
+        subset : object, default None
+            subset to act on
+        """
+        # create a new object to prevent aliasing
+        if subset is None:
+            subset = self.obj
+
+        # we need to make a shallow copy of ourselves
+        # with the same groupby
+        kwargs = dict([(attr, getattr(self, attr))
+                       for attr in self._attributes])
+        self = self.__class__(subset,
+                              groupby=self._groupby[key],
+                              parent=self,
+                              **kwargs)
+        self._reset_cache()
+        if subset.ndim == 2:
+            if is_scalar(key) and key in subset or is_list_like(key):
+                self._selection = key
+        return self
+
+
+# special case to prevent duplicate plots when catching exceptions when
+# forwarding methods from NDFrames
+plotting_methods = frozenset(['plot', 'boxplot', 'hist'])
+
+common_apply_whitelist = frozenset([
+    'last', 'first',
+    'head', 'tail', 'median',
+    'mean', 'sum', 'min', 'max',
+    'cumcount', 'ngroup',
+    'resample',
+    'rank', 'quantile',
+    'fillna',
+    'mad',
+    'any', 'all',
+    'take',
+    'idxmax', 'idxmin',
+    'shift', 'tshift',
+    'ffill', 'bfill',
+    'pct_change', 'skew',
+    'corr', 'cov', 'diff',
+]) | plotting_methods
+
+series_apply_whitelist = ((common_apply_whitelist |
+                           {'nlargest', 'nsmallest',
+                            'is_monotonic_increasing',
+                            'is_monotonic_decreasing'}) -
+                          {'boxplot'}) | frozenset(['dtype', 'unique'])
+
+dataframe_apply_whitelist = ((common_apply_whitelist |
+                              frozenset(['dtypes', 'corrwith'])) -
+                             {'boxplot'})
+
+cython_transforms = frozenset(['cumprod', 'cumsum', 'shift',
+                               'cummin', 'cummax'])
+
+cython_cast_blacklist = frozenset(['rank', 'count', 'size'])
+
+
+def whitelist_method_generator(base, klass, whitelist):
+    """
+    Yields all GroupBy member defs for DataFrame/Series names in whitelist.
+
+    Parameters
+    ----------
+    base : class
+        base class
+    klass : class
+        class where members are defined.
+        Should be Series or DataFrame
+    whitelist : list
+        list of names of klass methods to be constructed
+
+    Returns
+    -------
+    The generator yields a sequence of strings, each suitable for exec'ing,
+    that define implementations of the named methods for DataFrameGroupBy
+    or SeriesGroupBy.
+
+    Since we don't want to override methods explicitly defined in the
+    base class, any such name is skipped.
+    """
+
+    method_wrapper_template = \
+        """def %(name)s(%(sig)s) :
+    \"""
+    %(doc)s
+    \"""
+    f = %(self)s.__getattr__('%(name)s')
+    return f(%(args)s)"""
+    property_wrapper_template = \
+        """@property
+def %(name)s(self) :
+    \"""
+    %(doc)s
+    \"""
+    return self.__getattr__('%(name)s')"""
+
+    for name in whitelist:
+        # don't override anything that was explicitly defined
+        # in the base class
+        if hasattr(base, name):
+            continue
+        # ugly, but we need the name string itself in the method.
+        f = getattr(klass, name)
+        doc = f.__doc__
+        doc = doc if type(doc) == str else ''
+        if isinstance(f, types.MethodType):
+            wrapper_template = method_wrapper_template
+            decl, args = make_signature(f)
+            # pass args by name to f because otherwise
+            # GroupBy._make_wrapper won't know whether
+            # we passed in an axis parameter.
+            args_by_name = ['{0}={0}'.format(arg) for arg in args[1:]]
+            params = {'name': name,
+                      'doc': doc,
+                      'sig': ','.join(decl),
+                      'self': args[0],
+                      'args': ','.join(args_by_name)}
+        else:
+            wrapper_template = property_wrapper_template
+            params = {'name': name, 'doc': doc}
+        yield wrapper_template % params