BUG: closes #780, compare float to within 32bit precision

Author: adamklein

pandas/core/indexing.py

@@ -315,10 +315,13 @@ def _get_slice_axis(self, slice_obj, axis=0):
 
         return self._slice(slicer, axis=axis)
 
+# 32-bit floating point machine epsilon
+_eps = np.finfo('f4').eps
 
 def _is_index_slice(obj):
     def _is_valid_index(x):
-        return com.is_integer(x) or com.is_float(x) and np.allclose(x, int(x))
+        return (com.is_integer(x) or com.is_float(x)
+                and np.allclose(x, int(x), rtol=_eps, atol=0))
 
     def _crit(v):
         return v is None or _is_valid_index(v)

pandas/tests/test_frame.py

@@ -395,6 +395,19 @@ def test_getitem_fancy_2d(self):
         exp.values[5:10] = 5
         assert_frame_equal(f, exp)
 
+    def test_slice_floats(self):
+        index = [52195.504153, 52196.303147, 52198.369883]
+        df = DataFrame(np.random.rand(3, 2), index=index)
+
+        s1 = df.ix[52195.1:52196.5]
+        self.assertEquals(len(s1), 2)
+
+        s1 = df.ix[52195.1:52196.6]
+        self.assertEquals(len(s1), 2)
+
+        s1 = df.ix[52195.1:52198.9]
+        self.assertEquals(len(s1), 3)
+
     def test_getitem_fancy_slice_integers_step(self):
         df = DataFrame(np.random.randn(10, 5))