Deprecate NDFrame.swapaxes

Author: topper-123

doc/source/whatsnew/v0.25.0.rst

@@ -476,6 +476,8 @@ Other Deprecations
   the :meth:`SparseArray.to_dense` method instead (:issue:`26421`).
 - The functions :func:`pandas.to_datetime` and :func:`pandas.to_timedelta` have deprecated the ``box`` keyword. Instead, use :meth:`to_numpy` or :meth:`Timestamp.to_datetime64` or :meth:`Timedelta.to_timedelta64`. (:issue:`24416`)
 - The :meth:`DataFrame.compound` and :meth:`Series.compound` methods are deprecated and will be removed in a future version (:issue:`26405`).
+- The :meth:`DataFrame.swapaxes` and :meth:`Series.swapaxes` methods are deprecated and will be removed in a future version.
+  Use :meth:`DataFrame.transpose` and :meth:`Series.transpose` instead(:issue:`26654`).
 
 .. _whatsnew_0250.prior_deprecations:
 

pandas/core/generic.py

@@ -695,10 +695,17 @@ def swapaxes(self, axis1, axis2, copy=True):
         """
         Interchange axes and swap values axes appropriately.
 
+        .. deprecated:: 0.25.0
+            Use ``.T`` or ``.transpose()`` instead.
+
         Returns
         -------
         y : same as input
         """
+        warnings.warn("{obj}.swapaxes is deprecated and will be removed "
+                      "in a future version. Use {obj}.T or {obj}.transpose() "
+                      "instead".format(obj=type(self).__name__),
+                      FutureWarning, stacklevel=2)
         i = self._get_axis_number(axis1)
         j = self._get_axis_number(axis2)
 

pandas/core/groupby/ops.py

@@ -468,14 +468,14 @@ def _cython_operation(self, kind, values, how, axis, min_count=-1,
         arity = self._cython_arity.get(how, 1)
 
         vdim = values.ndim
-        swapped = False
+        transposed = False
         if vdim == 1:
             values = values[:, None]
             out_shape = (self.ngroups, arity)
         else:
             if axis > 0:
-                swapped = True
-                values = values.swapaxes(0, axis)
+                transposed = True
+                values = values.transpose()
             if arity > 1:
                 raise NotImplementedError("arity of more than 1 is not "
                                           "supported for the 'how' argument")
@@ -567,8 +567,8 @@ def _cython_operation(self, kind, values, how, axis, min_count=-1,
         else:
             names = None
 
-        if swapped:
-            result = result.swapaxes(0, axis)
+        if transposed:
+            result = result.transpose()
 
         return result, names
 

pandas/tests/frame/test_api.py

@@ -363,15 +363,13 @@ def test_transpose(self, float_frame):
         for col, s in mixed_T.items():
             assert s.dtype == np.object_
 
-    def test_swapaxes(self):
+    def test_swapaxes_deprecated(self):
         df = self.klass(np.random.randn(10, 5))
-        self._assert_frame_equal(df.T, df.swapaxes(0, 1))
-        self._assert_frame_equal(df.T, df.swapaxes(1, 0))
-        self._assert_frame_equal(df, df.swapaxes(0, 0))
-        msg = ("No axis named 2 for object type"
-               r" <class 'pandas.core(.sparse)?.frame.(Sparse)?DataFrame'>")
-        with pytest.raises(ValueError, match=msg):
-            df.swapaxes(2, 5)
+
+        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False):
+            swapped = df.swapaxes(0, 1)
+
+        tm.assert_frame_equal(swapped, df.T)
 
     def test_axis_aliases(self, float_frame):
         f = float_frame