Simplify logic of DataFrame.empty

Add test for empty method

Author: mroeschke

pandas/core/generic.py

@@ -909,7 +909,7 @@ def empty(self):
         pandas.Series.dropna
         pandas.DataFrame.dropna
         """
-        return not all(len(self._get_axis(a)) > 0 for a in self._AXIS_ORDERS)
+        return any(len(self._get_axis(a)) == 0 for a in self._AXIS_ORDERS)
 
     def __nonzero__(self):
         raise ValueError("The truth value of a {0} is ambiguous. "

pandas/tests/test_generic.py

@@ -881,6 +881,13 @@ def testit(index, check_index_type=True, check_categorical=True):
         self.assertIsInstance(result, DataArray)
         assert_series_equal(result.to_series(), s)
 
+    def test_empty_method(self):
+        s_empty = pd.Series()
+        tm.assert_equal(s_empty.empty, True)
+
+        for full_series in [pd.Series([1]), pd.Series(index=[1])]:
+            tm.assert_equal(full_series.empty, False)
+
 
 class TestDataFrame(tm.TestCase, Generic):
     _typ = DataFrame
@@ -1504,6 +1511,20 @@ def test_to_xarray(self):
                            expected,
                            check_index_type=False)
 
+    def test_empty_method(self):
+        empty_frames = [pd.DataFrame(),
+                        pd.DataFrame(index=[1]),
+                        pd.DataFrame(columns=[1]),
+                        pd.DataFrame({1: []})]
+        for frame in empty_frames:
+            tm.assert_equal(frame.empty, True)
+
+        full_frames = [pd.DataFrame([1]),
+                       pd.DataFrame(index=[1], columns=[1]),
+                       pd.DataFrame({1: [1]})]
+        for frame in full_frames:
+            tm.assert_equal(frame.empty, False)
+
 
 class TestPanel(tm.TestCase, Generic):
     _typ = Panel