fixes pandas-dev#22085

Author: a1shadows

pandas/core/indexes/base.py

@@ -1949,6 +1949,9 @@ def __nonzero__(self):
     def __contains__(self, key):
         hash(key)
         try:
+            if type(key) == float and self.dtype == int:
+                if key != int(key):
+                    return False
             return key in self._engine
         except (OverflowError, TypeError, ValueError):
             return False