Merge pull request #11291 from BrenBarn/pytables-fix

Fix mistake in Pytables querying with numpy scalar value.  Fixes #11283

Author: jreback

doc/source/whatsnew/v0.17.1.txt

@@ -55,7 +55,7 @@ Bug Fixes
 
 - Bug in ``.to_latex()`` output broken when the index has a name (:issue: `10660`)
 - Bug in ``HDFStore.append`` with strings whose encoded length exceded the max unencoded length (:issue:`11234`)
-
+- Bug in ``HDFStore.select`` when comparing with a numpy scalar in a where clause (:issue:`11283`)
 
 
 

pandas/computation/pytables.py

@@ -129,7 +129,7 @@ def conform(self, rhs):
         """ inplace conform rhs """
         if not com.is_list_like(rhs):
             rhs = [rhs]
-        if hasattr(self.rhs, 'ravel'):
+        if isinstance(rhs, np.ndarray):
             rhs = rhs.ravel()
         return rhs
 

pandas/io/tests/test_pytables.py

@@ -3049,6 +3049,18 @@ def test_select_dtypes(self):
             result = store.select(
                 'df4', where='values>2.0')
             tm.assert_frame_equal(expected, result)
+        
+        # test selection with comparison against numpy scalar
+        # GH 11283
+        with ensure_clean_store(self.path) as store:
+            df = tm.makeDataFrame()
+
+            expected = df[df['A']>0]
+
+            store.append('df', df, data_columns=True)
+            np_zero = np.float64(0)
+            result = store.select('df', where=["A>np_zero"])
+            tm.assert_frame_equal(expected, result)
 
     def test_select_with_many_inputs(self):