From ab452001b610b697ed14150f9d99ae1b3fcf225d Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Fri, 10 Jan 2020 11:17:35 -0800
Subject: [PATCH 1/2] raise earlier in RangeIndex.get_loc

---
 pandas/core/indexes/range.py              | 17 ++++++++++-------
 pandas/tests/indexes/ranges/test_range.py |  7 ++++---
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index b4cc71a25792f..510943ef22695 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -14,6 +14,7 @@
 from pandas.core.dtypes.common import (
     ensure_platform_int,
     ensure_python_int,
+    is_float,
     is_integer,
     is_integer_dtype,
     is_list_like,
@@ -111,7 +112,7 @@ def __new__(
         return cls._simple_new(rng, dtype=dtype, name=name)
 
     @classmethod
-    def from_range(cls, data, name=None, dtype=None):
+    def from_range(cls, data: range, name=None, dtype=None):
         """
         Create RangeIndex from a range object.
 
@@ -344,12 +345,14 @@ def __contains__(self, key: Union[int, np.integer]) -> bool:
 
     @Appender(_index_shared_docs["get_loc"])
     def get_loc(self, key, method=None, tolerance=None):
-        if is_integer(key) and method is None and tolerance is None:
-            new_key = int(key)
-            try:
-                return self._range.index(new_key)
-            except ValueError:
-                raise KeyError(key)
+        if method is None and tolerance is None:
+            if is_integer(key) or (is_float(key) and key.is_integer()):
+                new_key = int(key)
+                try:
+                    return self._range.index(new_key)
+                except ValueError:
+                    raise KeyError(key)
+            raise KeyError(key)
         return super().get_loc(key, method=method, tolerance=tolerance)
 
     @Appender(_index_shared_docs["get_indexer"])
diff --git a/pandas/tests/indexes/ranges/test_range.py b/pandas/tests/indexes/ranges/test_range.py
index 8d98ab18963b6..0e5d1d45ad6db 100644
--- a/pandas/tests/indexes/ranges/test_range.py
+++ b/pandas/tests/indexes/ranges/test_range.py
@@ -735,8 +735,9 @@ def test_engineless_lookup(self):
 
         assert "_engine" not in idx._cache
 
-        # The engine is still required for lookup of a different dtype scalar:
+        # Different types of scalars can be excluded immediately, no need to
+        #  use the _engine
         with pytest.raises(KeyError, match="'a'"):
-            assert idx.get_loc("a") == -1
+            idx.get_loc("a")
 
-        assert "_engine" in idx._cache
+        assert "_engine" not in idx._cache

From 4b5ba7e29f5b39de43076fe9a925ee43a7015ca5 Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Fri, 10 Jan 2020 15:03:02 -0800
Subject: [PATCH 2/2] revert

---
 pandas/core/indexes/range.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 510943ef22695..5c79942efb908 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -112,7 +112,7 @@ def __new__(
         return cls._simple_new(rng, dtype=dtype, name=name)
 
     @classmethod
-    def from_range(cls, data: range, name=None, dtype=None):
+    def from_range(cls, data, name=None, dtype=None):
         """
         Create RangeIndex from a range object.