ENH: df.__getitem__ accepts zerodim integer np.array, and add test

Author: tamuhey

Diff for: pandas/core/frame.py

@@ -2881,6 +2881,7 @@ def _ixs(self, i, axis=0):
                 return result
 
     def __getitem__(self, key):
+        key = lib.item_from_zerodim(key)
         key = com.apply_if_callable(key, self)
 
         # shortcut if the key is in columns

Diff for: pandas/tests/frame/test_indexing.py

@@ -3682,3 +3682,14 @@ def test_functions_no_warnings(self):
         with tm.assert_produces_warning(False):
             df['group'] = pd.cut(df.value, range(0, 105, 10), right=False,
                                  labels=labels)
+
+    def test_getitem_zerodim_np_array(self):
+        # GH24924
+        df = DataFrame([[1, 2], [3, 4]])
+
+        # should not raise an error
+        result = df[np.array(0)]
+
+        # expected series
+        sr = pd.Series([1, 3], name=0)
+        tm.assert_series_equal(result, sr)