DEPR: DataFrame.swapaxes

pandas/core/generic.py

@@ -741,6 +741,15 @@ def swapaxes(
         -------
         same as input
         """
+        warnings.warn(
+            # GH#51946
+            f"'{type(self).__name__}.swapaxes' is deprecated and \
+                will be removed in a future version. \
+                Please use '{type(self).__name__}.transpose' instead.",
+            FutureWarning,
+            stacklevel=find_stack_level(),
+        )
+
         i = self._get_axis_number(axis1)
         j = self._get_axis_number(axis2)
 

pandas/tests/copy_view/test_methods.py

@@ -72,7 +72,7 @@ def test_copy_shallow(using_copy_on_write):
         lambda df, copy: df.rename_axis(columns="test", copy=copy),
         lambda df, copy: df.astype({"b": "int64"}, copy=copy),
         # lambda df, copy: df.swaplevel(0, 0, copy=copy),
-        lambda df, copy: df.swapaxes(0, 0, copy=copy),
+        # lambda df, copy: df.swapaxes(0, 0, copy=copy),
         lambda df, copy: df.truncate(0, 5, copy=copy),
         lambda df, copy: df.infer_objects(copy=copy),
         lambda df, copy: df.to_timestamp(copy=copy),
@@ -91,7 +91,6 @@ def test_copy_shallow(using_copy_on_write):
         "rename_axis1",
         "astype",
         # "swaplevel",  # only series
-        "swapaxes",
         "truncate",
         "infer_objects",
         "to_timestamp",
@@ -142,7 +141,7 @@ def test_methods_copy_keyword(
         lambda ser, copy: ser.rename_axis(index="test", copy=copy),
         lambda ser, copy: ser.astype("int64", copy=copy),
         lambda ser, copy: ser.swaplevel(0, 1, copy=copy),
-        lambda ser, copy: ser.swapaxes(0, 0, copy=copy),
+        # lambda ser, copy: ser.swapaxes(0, 0, copy=copy),
         lambda ser, copy: ser.truncate(0, 5, copy=copy),
         lambda ser, copy: ser.infer_objects(copy=copy),
         lambda ser, copy: ser.to_timestamp(copy=copy),
@@ -160,7 +159,6 @@ def test_methods_copy_keyword(
         "rename_axis0",
         "astype",
         "swaplevel",
-        "swapaxes",
         "truncate",
         "infer_objects",
         "to_timestamp",
@@ -610,7 +608,9 @@ def test_to_frame(using_copy_on_write):
 def test_swapaxes_noop(using_copy_on_write, ax):
     df = DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]})
     df_orig = df.copy()
-    df2 = df.swapaxes(ax, ax)
+    msg = "'DataFrame.swapaxes' is deprecated"
+    with tm.assert_produces_warning(FutureWarning, match=msg):
+        df2 = df.swapaxes(ax, ax)
 
     if using_copy_on_write:
         assert np.shares_memory(get_array(df2, "a"), get_array(df, "a"))
@@ -627,7 +627,9 @@ def test_swapaxes_noop(using_copy_on_write, ax):
 def test_swapaxes_single_block(using_copy_on_write):
     df = DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]}, index=["x", "y", "z"])
     df_orig = df.copy()
-    df2 = df.swapaxes("index", "columns")
+    msg = "'DataFrame.swapaxes' is deprecated"
+    with tm.assert_produces_warning(FutureWarning, match=msg):
+        df2 = df.swapaxes("index", "columns")
 
     if using_copy_on_write:
         assert np.shares_memory(get_array(df2, "x"), get_array(df, "a"))

pandas/tests/extension/base/dim2.py

@@ -37,8 +37,9 @@ def test_frame_from_2d_array(self, data):
 
     def test_swapaxes(self, data):
         arr2d = data.repeat(2).reshape(-1, 2)
-
-        result = arr2d.swapaxes(0, 1)
+        msg = "'DataFrame.swapaxes' is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = arr2d.swapaxes(0, 1)
         expected = arr2d.T
         self.assert_extension_array_equal(result, expected)
 

pandas/tests/frame/methods/test_swapaxes.py

@@ -8,22 +8,30 @@
 class TestSwapAxes:
     def test_swapaxes(self):
         df = DataFrame(np.random.randn(10, 5))
-        tm.assert_frame_equal(df.T, df.swapaxes(0, 1))
-        tm.assert_frame_equal(df.T, df.swapaxes(1, 0))
+        msg = "'DataFrame.swapaxes' is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            tm.assert_frame_equal(df.T, df.swapaxes(0, 1))
+            tm.assert_frame_equal(df.T, df.swapaxes(1, 0))
 
     def test_swapaxes_noop(self):
         df = DataFrame(np.random.randn(10, 5))
-        tm.assert_frame_equal(df, df.swapaxes(0, 0))
+        msg = "'DataFrame.swapaxes' is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            tm.assert_frame_equal(df, df.swapaxes(0, 0))
 
     def test_swapaxes_invalid_axis(self):
         df = DataFrame(np.random.randn(10, 5))
-        msg = "No axis named 2 for object type DataFrame"
-        with pytest.raises(ValueError, match=msg):
-            df.swapaxes(2, 5)
+        msg = "'DataFrame.swapaxes' is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            msg = "No axis named 2 for object type DataFrame"
+            with pytest.raises(ValueError, match=msg):
+                df.swapaxes(2, 5)
 
     def test_round_empty_not_input(self):
         # GH#51032
         df = DataFrame({"a": [1, 2]})
-        result = df.swapaxes("index", "index")
+        msg = "'DataFrame.swapaxes' is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = df.swapaxes("index", "index")
         tm.assert_frame_equal(df, result)
         assert df is not result

pandas/tests/generic/test_finalize.py

@@ -251,7 +251,6 @@
             operator.methodcaller("isin", pd.DataFrame({"A": [1]})),
         ),
     ),
-    (pd.DataFrame, frame_data, operator.methodcaller("swapaxes", 0, 1)),
     (pd.DataFrame, frame_mi_data, operator.methodcaller("droplevel", "A")),
     (pd.DataFrame, frame_data, operator.methodcaller("pop", "A")),
     pytest.param(