add deprecation code

Author: topper-123

pandas/core/indexes/range.py

@@ -233,6 +233,10 @@ def _format_with_header(self, header, na_rep='NaN', **kwargs):
         return header + list(map(pprint_thing, self._range))
 
     # --------------------------------------------------------------------
+    _deprecation_message = ("RangeIndex.{} is deprecated and will be "
+                            "removed in a future version. Use RangeIndex.{} "
+                            "instead")
+
     @cache_readonly
     def start(self):
         """
@@ -249,6 +253,8 @@ def _start(self):
          .. deprecated:: 0.25.0
             Use ``start`` instead.
         """
+        warnings.warn(self._deprecation_message.format("_start", "start"),
+                      DeprecationWarning, stacklevel=2)
         return self.start
 
     @cache_readonly
@@ -267,6 +273,8 @@ def _stop(self):
             Use ``stop`` instead.
         """
         # GH 25710
+        warnings.warn(self._deprecation_message.format("_stop", "stop"),
+                      DeprecationWarning, stacklevel=2)
         return self.stop
 
     @cache_readonly
@@ -286,6 +294,8 @@ def _step(self):
             Use ``step`` instead.
         """
         # GH 25710
+        warnings.warn(self._deprecation_message.format("_step", "step"),
+                      DeprecationWarning, stacklevel=2)
         return self.step
 
     @cache_readonly

pandas/tests/indexes/test_range.py

@@ -167,6 +167,13 @@ def test_start_stop_step_attrs(self, index, start, stop, step):
         assert index.stop == stop
         assert index.step == step
 
+    def test_deprecated_start_stop_step_attrs(self):
+        # GH 26581
+        idx = self.create_index()
+        for attr_name in ['_start', '_stop', '_step']:
+            with tm.assert_produces_warning(DeprecationWarning):
+                getattr(idx, attr_name)
+
     def test_copy(self):
         i = RangeIndex(5, name='Foo')
         i_copy = i.copy()