Prevent tuple sublcass instances from being recognized as "list-like".

Close #1026

Author: Eric Chlebek

pandas/core/indexing.py

@@ -486,7 +486,10 @@ def _is_label_like(key):
 
 
 def _is_list_like(obj):
-    return np.iterable(obj) and not isinstance(obj, basestring)
+    # Consider namedtuples to be not list like as they are useful as indices
+    return (np.iterable(obj)
+            and not isinstance(obj, basestring)
+            and not (isinstance(obj, tuple) and type(obj) is not tuple))
 
 
 def _need_slice(obj):

pandas/tests/test_frame.py

@@ -5122,7 +5122,6 @@ def test_stale_cached_series_bug_473(self):
 
     def test_index_namedtuple(self):
         # Skipping until 1026 is properly resolved
-        raise nose.SkipTest
         from collections import namedtuple
         IndexType = namedtuple("IndexType", ["a", "b"])
         idx1 = IndexType("foo", "bar")