Transition to _make_accessor

flake8 fixes

Update import name

Author: jbrockmendel

pandas/core/accessors.py

@@ -74,9 +74,9 @@ def _make_accessor(cls, data):
 
 With `_make_accessor` defined, we have enough to create the accessor, but
 not enough to actually do anything useful with it.  In order to access
-*methods* of State objects, we implement `_delegate_method`.  `_delegate_method`
-calls the underlying method for each object in the series and wraps these
-in a new Series.  The simplest version looks like:
+*methods* of State objects, we implement `_delegate_method`.
+`_delegate_method` calls the underlying method for each object in the
+series and wraps these in a new Series.  The simplest version looks like:
 
     def _delegate_method(self, name, *args, **kwargs):
         state_method = lambda x: getattr(x, name)(*args, **kwargs)
@@ -150,6 +150,7 @@ class StateDelegate(PandasDelegate):
 from pandas.core.base import PandasObject
 from pandas.core import common as com
 
+
 class PandasDelegate(PandasObject):
     """ an abstract base class for delegating methods/properties
 
@@ -164,12 +165,12 @@ def __init__(self, values):
 
     @classmethod
     def _make_accessor(cls, data):  # pragma: no cover
-        raise NotImplementedError('It is up to subclasses to implement '
+        raise NotImplementedError(
+            'It is up to subclasses to implement '
             '_make_accessor.  This does input validation on the object to '
             'which the accessor is being pinned.  '
             'It should return an instance of `cls`.')
 
-
     def _delegate_property_get(self, name, *args, **kwargs):
         raise TypeError("You cannot access the "
                         "property {name}".format(name=name))
@@ -181,7 +182,6 @@ def _delegate_method(self, name, *args, **kwargs):
         raise TypeError("You cannot call method {name}".format(name=name))
 
 
-
 class AccessorProperty(object):
     """Descriptor for implementing accessor properties like Series.str
     """
@@ -235,7 +235,6 @@ def _setter(self, new_values):
         _doc = getattr(delegate, name).__doc__
         return property(fget=_getter, fset=_setter, doc=_doc)
 
-
     @staticmethod
     def create_delegator_method(name, delegate):
         # Note: we really only need the `delegate` here for the docstring
@@ -246,14 +245,13 @@ def func(self, *args, **kwargs):
         if callable(name):
             # A function/method was passed directly instead of a name
             # This may also render the `delegate` arg unnecessary.
-            func.__name__ = name.__name__ # TODO: is this generally valid?
+            func.__name__ = name.__name__  # TODO: is this generally valid?
             func.__doc__ = name.__doc__
         else:
             func.__name__ = name
             func.__doc__ = getattr(delegate, name).__doc__
         return func
 
-
     @staticmethod
     def delegate_names(delegate, accessors, typ, overwrite=False):
         """
@@ -309,7 +307,6 @@ def add_delegate_accessors(cls):
         return add_delegate_accessors
 
 
-
 wrap_delegate_names = Delegator.delegate_names
 # TODO: the `delegate` arg to `wrap_delegate_names` is really only relevant
 # for a docstring.  It'd be nice if we didn't require it and could duck-type
@@ -346,6 +343,3 @@ def add_delegate_accessors(cls):
 # The third thing to consider moving into the general case is
 # core.strings.StringMethods._wrap_result, which handles a bunch of cases
 # for how to wrap delegated outputs.
-
-
-

pandas/core/base.py

@@ -162,10 +162,6 @@ def __setattr__(self, key, value):
         object.__setattr__(self, key, value)
 
 
-
-
-
-
 class GroupByError(Exception):
     pass
 

pandas/core/categorical.py

@@ -29,7 +29,7 @@
 from pandas.core.common import is_null_slice
 
 from pandas.core.algorithms import factorize, take_1d, unique1d
-from pandas.core.accessors import PandasDelegate
+from pandas.core import accessors
 from pandas.core.base import (PandasObject,
                               NoNewAttributesMixin, _shared_docs)
 import pandas.core.common as com
@@ -2014,7 +2014,20 @@ def repeat(self, repeats, *args, **kwargs):
 # The Series.cat accessor
 
 
-class CategoricalAccessor(PandasDelegate, NoNewAttributesMixin):
+@accessors.wrap_delegate_names(delegate=Categorical,
+                               accessors=["rename_categories",
+                                          "reorder_categories",
+                                          "add_categories",
+                                          "remove_categories",
+                                          "remove_unused_categories",
+                                          "set_categories",
+                                          "as_ordered",
+                                          "as_unordered"],
+                               typ="method")
+@accessors.wrap_delegate_names(delegate=Categorical,
+                               accessors=["categories", "ordered"],
+                               typ="property")
+class CategoricalAccessor(accessors.PandasDelegate, NoNewAttributesMixin):
     """
     Accessor object for categorical properties of the Series values.
 
@@ -2037,6 +2050,13 @@ class CategoricalAccessor(PandasDelegate, NoNewAttributesMixin):
 
     """
 
+    @classmethod
+    def _make_accessor(cls, values):
+        if not is_categorical_dtype(values.dtype):
+            msg = "Can only use .cat accessor with a 'category' dtype"
+            raise AttributeError(msg)
+        return CategoricalAccessor(values.values, values.index)
+
     def __init__(self, values, index):
         self.categorical = values
         self.index = index
@@ -2048,31 +2068,23 @@ def _delegate_property_get(self, name):
     def _delegate_property_set(self, name, new_values):
         return setattr(self.categorical, name, new_values)
 
-    @property
-    def codes(self):
-        from pandas import Series
-        return Series(self.categorical.codes, index=self.index)
-
     def _delegate_method(self, name, *args, **kwargs):
         from pandas import Series
         method = getattr(self.categorical, name)
         res = method(*args, **kwargs)
         if res is not None:
             return Series(res, index=self.index)
 
+    # TODO: Can we get this from _delegate_property_get?
+    # Would need to get self.index into the result
+    @property
+    def codes(self):
+        from pandas import Series
+        return Series(self.categorical.codes, index=self.index)
 
-CategoricalAccessor._add_delegate_accessors(delegate=Categorical,
-                                            accessors=["categories",
-                                                       "ordered"],
-                                            typ='property')
-CategoricalAccessor._add_delegate_accessors(delegate=Categorical, accessors=[
-    "rename_categories", "reorder_categories", "add_categories",
-    "remove_categories", "remove_unused_categories", "set_categories",
-    "as_ordered", "as_unordered"], typ='method')
 
 # utility routines
 
-
 def _get_codes_for_values(values, categories):
     """
     utility routine to turn values into codes given the specified categories

pandas/core/frame.py

@@ -88,7 +88,7 @@
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
 
-from pandas.core import accessors, base, nanops, ops
+from pandas.core import accessors, nanops, ops
 import pandas.core.common as com
 
 import pandas.io.formats.format as fmt
@@ -6006,7 +6006,7 @@ def _put_str(s, space):
 # ----------------------------------------------------------------------
 # Add plotting methods to DataFrame
 DataFrame.plot = accessors.AccessorProperty(gfx.FramePlotMethods,
-                                       gfx.FramePlotMethods)
+                                            gfx.FramePlotMethods)
 DataFrame.hist = gfx.hist_frame
 
 

pandas/core/indexes/accessors.py

@@ -11,7 +11,8 @@
     is_timedelta64_dtype, is_categorical_dtype,
     is_list_like)
 
-from pandas.core.accessors import PandasDelegate
+from pandas.core import accessors
+
 from pandas.core.base import NoNewAttributesMixin
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas._libs.period import IncompatibleFrequency  # noqa
@@ -85,7 +86,7 @@ def maybe_to_datetimelike(data, copy=False):
                     "datetimelike index".format(type(data)))
 
 
-class Properties(PandasDelegate, NoNewAttributesMixin):
+class BaseDatetimeAccessor(accessors.PandasDelegate, NoNewAttributesMixin):
 
     def __init__(self, values, index, name, orig=None):
         self.values = values
@@ -95,7 +96,7 @@ def __init__(self, values, index, name, orig=None):
         self._freeze()
 
     def _delegate_property_get(self, name):
-        from pandas import Series
+        from pandas import Series, DataFrame
 
         result = getattr(self.values, name)
 
@@ -105,6 +106,9 @@ def _delegate_property_get(self, name):
                 result = result.astype('int64')
         elif not is_list_like(result):
             return result
+        elif isinstance(result, DataFrame):
+            # e.g. TimedeltaProperties.components
+            return result.set_index(self.index)
 
         result = np.asarray(result)
 
@@ -146,7 +150,18 @@ def _delegate_method(self, name, *args, **kwargs):
         return result
 
 
-class DatetimeProperties(Properties):
+# An alternative to decorating with @accessors.wrap_delegate_names
+# is to define each method individually, e.g.:
+# to_period = PandasDelegate._make_delegate_accessor(delegate=DatetimeIndex,
+#                                                    name='to_period',
+#                                                    typ='method')
+@accessors.wrap_delegate_names(delegate=DatetimeIndex,
+                               accessors=DatetimeIndex._datetimelike_ops,
+                               typ='property')
+@accessors.wrap_delegate_names(delegate=DatetimeIndex,
+                               accessors=DatetimeIndex._datetimelike_methods,
+                               typ='method')
+class DatetimeProperties(BaseDatetimeAccessor):
     """
     Accessor object for datetimelike properties of the Series values.
 
@@ -164,17 +179,13 @@ def to_pydatetime(self):
         return self.values.to_pydatetime()
 
 
-DatetimeProperties._add_delegate_accessors(
-    delegate=DatetimeIndex,
-    accessors=DatetimeIndex._datetimelike_ops,
-    typ='property')
-DatetimeProperties._add_delegate_accessors(
-    delegate=DatetimeIndex,
-    accessors=DatetimeIndex._datetimelike_methods,
-    typ='method')
-
-
-class TimedeltaProperties(Properties):
+@accessors.wrap_delegate_names(delegate=TimedeltaIndex,
+                               accessors=TimedeltaIndex._datetimelike_ops,
+                               typ='property')
+@accessors.wrap_delegate_names(delegate=TimedeltaIndex,
+                               accessors=TimedeltaIndex._datetimelike_methods,
+                               typ='method')
+class TimedeltaProperties(BaseDatetimeAccessor):
     """
     Accessor object for datetimelike properties of the Series values.
 
@@ -190,6 +201,7 @@ class TimedeltaProperties(Properties):
     def to_pytimedelta(self):
         return self.values.to_pytimedelta()
 
+    # TODO: Do this with wrap_delegate_names
     @property
     def components(self):
         """
@@ -204,17 +216,13 @@ def components(self):
         return self.values.components.set_index(self.index)
 
 
-TimedeltaProperties._add_delegate_accessors(
-    delegate=TimedeltaIndex,
-    accessors=TimedeltaIndex._datetimelike_ops,
-    typ='property')
-TimedeltaProperties._add_delegate_accessors(
-    delegate=TimedeltaIndex,
-    accessors=TimedeltaIndex._datetimelike_methods,
-    typ='method')
-
-
-class PeriodProperties(Properties):
+@accessors.wrap_delegate_names(delegate=PeriodIndex,
+                               accessors=PeriodIndex._datetimelike_ops,
+                               typ='property')
+@accessors.wrap_delegate_names(delegate=PeriodIndex,
+                               accessors=PeriodIndex._datetimelike_methods,
+                               typ='method')
+class PeriodProperties(BaseDatetimeAccessor):
     """
     Accessor object for datetimelike properties of the Series values.
 
@@ -229,18 +237,20 @@ class PeriodProperties(Properties):
     """
 
 
-PeriodProperties._add_delegate_accessors(
-    delegate=PeriodIndex,
-    accessors=PeriodIndex._datetimelike_ops,
-    typ='property')
-PeriodProperties._add_delegate_accessors(
-    delegate=PeriodIndex,
-    accessors=PeriodIndex._datetimelike_methods,
-    typ='method')
-
-
 class CombinedDatetimelikeProperties(DatetimeProperties, TimedeltaProperties):
     # This class is never instantiated, and exists solely for the benefit of
     # the Series.dt class property. For Series objects, .dt will always be one
     # of the more specific classes above.
     __doc__ = DatetimeProperties.__doc__
+
+    @classmethod
+    def _make_accessor(cls, values):
+        try:
+            return maybe_to_datetimelike(values)
+        except Exception:
+            msg = "Can only use .dt accessor with datetimelike values"
+            raise AttributeError(msg)
+
+
+DatetimeAccessor = CombinedDatetimelikeProperties
+# Alias to mirror CategoricalAccessor