From aa3f2220d95c3c44ebee11a38727c2ca7b7bdf4f Mon Sep 17 00:00:00 2001
From: Scott Sanderson <ssanderson@quantopian.com>
Date: Tue, 22 Nov 2016 17:11:04 -0500
Subject: [PATCH] MAINT: Hit more dataframe indexers.

---
 zipline/utils/pandas_utils.py | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/zipline/utils/pandas_utils.py b/zipline/utils/pandas_utils.py
index 1b81897a..633960e1 100644
--- a/zipline/utils/pandas_utils.py
+++ b/zipline/utils/pandas_utils.py
@@ -168,19 +168,25 @@ def ignore_pandas_nan_categorical_warning():
         yield
 
 
+_INDEXER_NAMES = [
+    '_' + name for (name, _) in pd.core.indexing.get_indexers_list()
+]
+
+
 def clear_dataframe_indexer_caches(df):
     """
     Clear cached attributes from a pandas DataFrame.
 
-    By default pandas memoizes `iloc`, `loc` objects on DataFrames, resulting
-    in refcycles that can lead to unexpectedly long-lived DataFrames.  This
-    function attempts to clear those cycles.
+    By default pandas memoizes indexers (`iloc`, `loc`, `ix`, etc.) objects on
+    DataFrames, resulting in refcycles that can lead to unexpectedly long-lived
+    DataFrames. This function attempts to clear those cycles by deleting the
+    cached indexers from the frame.
 
     Parameters
     ----------
     df : pd.DataFrame
     """
-    for attr in ('_loc', '_iloc'):
+    for attr in _INDEXER_NAMES:
         try:
             delattr(df, attr)
         except AttributeError: