DEPR: Series ndarray properties (strides, data, base, itemsize, flags)

doc/source/whatsnew/v0.23.0.txt

@@ -877,6 +877,9 @@ Deprecations
 - The ``convert_datetime64`` parameter in :func:`DataFrame.to_records` has been deprecated and will be removed in a future version. The NumPy bug motivating this parameter has been resolved. The default value for this parameter has also changed from ``True`` to ``None`` (:issue:`18160`).
 - :func:`Series.rolling().apply() <pandas.core.window.Rolling.apply>`, :func:`DataFrame.rolling().apply() <pandas.core.window.Rolling.apply>`,
   :func:`Series.expanding().apply() <pandas.core.window.Expanding.apply>`, and :func:`DataFrame.expanding().apply() <pandas.core.window.Expanding.apply>` have deprecated passing an ``np.array`` by default. One will need to pass the new ``raw`` parameter to be explicit about what is passed (:issue:`20584`)
+- The ``data``, ``base``, ``strides``, ``flags`` and ``itemsize`` properties
+  of the ``Series`` and ``Index`` classes have been deprecated and will be
+  removed in a future version (:issue:`20419`).
 
 .. _whatsnew_0230.prior_deprecations:
 

pandas/core/base.py

@@ -737,11 +737,17 @@ def item(self):
     @property
     def data(self):
         """ return the data pointer of the underlying data """
+        warnings.warn("{obj}.data is deprecated and will be removed "
+                      "in a future version".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         return self.values.data
 
     @property
     def itemsize(self):
         """ return the size of the dtype of the item of the underlying data """
+        warnings.warn("{obj}.itemsize is deprecated and will be removed "
+                      "in a future version".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         return self._ndarray_values.itemsize
 
     @property
@@ -752,6 +758,9 @@ def nbytes(self):
     @property
     def strides(self):
         """ return the strides of the underlying data """
+        warnings.warn("{obj}.strudes is deprecated and will be removed "
+                      "in a future version".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         return self._ndarray_values.strides
 
     @property
@@ -762,13 +771,19 @@ def size(self):
     @property
     def flags(self):
         """ return the ndarray.flags for the underlying data """
+        warnings.warn("{obj}.flags is deprecated and will be removed "
+                      "in a future version".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         return self.values.flags
 
     @property
     def base(self):
         """ return the base object if the memory of the underlying data is
         shared
         """
+        warnings.warn("{obj}.base is deprecated and will be removed "
+                      "in a future version".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         return self.values.base
 
     @property

pandas/core/indexes/datetimelike.py

@@ -209,6 +209,16 @@ def ceil(self, freq):
 class DatetimeIndexOpsMixin(object):
     """ common ops mixin to support a unified interface datetimelike Index """
 
+    @property
+    def base(self):
+        """ return the base object if the memory of the underlying data is
+        shared
+        """
+        # override deprecated property in IndexOpsMixin, as we still need
+        # this for internals (DatetimeIndex/TimedeltaIndex is stored as
+        # values in Blocks)
+        return self.values.base
+
     def equals(self, other):
         """
         Determines if two Index objects contain the same elements.

pandas/tests/groupby/aggregate/test_other.py

@@ -328,7 +328,7 @@ def test_series_agg_multi_pure_python():
          'F': np.random.randn(11)})
 
     def bad(x):
-        assert (len(x.base) > 0)
+        assert (len(x.values.base) > 0)
         return 'foo'
 
     result = data.groupby(['A', 'B']).agg(bad)

pandas/tests/groupby/test_groupby.py

@@ -1618,7 +1618,7 @@ def convert_fast(x):
 
         def convert_force_pure(x):
             # base will be length 0
-            assert (len(x.base) > 0)
+            assert (len(x.values.base) > 0)
             return Decimal(str(x.mean()))
 
         grouped = s.groupby(labels)

pandas/tests/indexes/common.py

@@ -24,7 +24,7 @@
 class Base(object):
     """ base class for index sub-class tests """
     _holder = None
-    _compat_props = ['shape', 'ndim', 'size', 'itemsize', 'nbytes']
+    _compat_props = ['shape', 'ndim', 'size', 'nbytes']
 
     def setup_indices(self):
         for name, idx in self.indices.items():

pandas/tests/test_base.py

@@ -316,16 +316,25 @@ def test_ndarray_compat_properties(self):
 
         for o in self.objs:
             # Check that we work.
-            for p in ['shape', 'dtype', 'flags', 'T',
-                      'strides', 'itemsize', 'nbytes']:
+            for p in ['shape', 'dtype', 'T', 'nbytes']:
                 assert getattr(o, p, None) is not None
 
-            assert hasattr(o, 'base')
+            # deprecated properties
+            for p in ['flags', 'strides', 'itemsize']:
+                with tm.assert_produces_warning(FutureWarning):
+                    assert getattr(o, p, None) is not None
+
+            # not deprecated for datetime-like indices because they are used
+            # inside blocks
+            if not isinstance(o, (DatetimeIndex, TimedeltaIndex, PeriodIndex)):
+                with tm.assert_produces_warning(FutureWarning):
+                    assert hasattr(o, 'base')
 
             # If we have a datetime-like dtype then needs a view to work
             # but the user is responsible for that
             try:
-                assert o.data is not None
+                with tm.assert_produces_warning(FutureWarning):
+                    assert o.data is not None
             except ValueError:
                 pass