From f07a4071e6ecdf3ac4621616bb8623559e4caa5f Mon Sep 17 00:00:00 2001
From: TomAugspurger <thomas-augspurger@uiowa.edu>
Date: Tue, 22 Apr 2014 12:55:17 -0500
Subject: [PATCH] Deprecate order kwarg in factorize

---
 doc/source/release.rst     | 2 ++
 doc/source/v0.14.0.txt     | 1 +
 pandas/core/algorithms.py  | 7 ++++++-
 pandas/tests/test_algos.py | 6 ++++++
 4 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/doc/source/release.rst b/doc/source/release.rst
index e38d5e00a31ad..0ad7793285000 100644
--- a/doc/source/release.rst
+++ b/doc/source/release.rst
@@ -206,6 +206,8 @@ Deprecations
   ``periods`` with a default value of 1. A ``FutureWarning`` is raised if the
   old argument ``lags`` is used by name. (:issue:`6910`)
 
+- The ``order`` keyword argument of :func:`factorize` will be removed. (:issue:`6926`).
+
 Prior Version Deprecations/Changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/doc/source/v0.14.0.txt b/doc/source/v0.14.0.txt
index b3ee1fdef30a8..242c27ebbf9b0 100644
--- a/doc/source/v0.14.0.txt
+++ b/doc/source/v0.14.0.txt
@@ -420,6 +420,7 @@ Deprecations
   The old positional argument ``lags`` has been changed to a keyword argument
   ``periods`` with a default value of 1. A ``FutureWarning`` is raised if the
   old argument ``lags`` is used by name. (:issue:`6910`)
+- The ``order`` keyword argument of :func:`factorize` will be removed. (:issue:`6926`).
 
 .. _whatsnew_0140.enhancements:
 
diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index e2ef178c62e71..5efba4a9738af 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -11,6 +11,7 @@
 import pandas.hashtable as htable
 import pandas.compat as compat
 from pandas.compat import filter, string_types
+from pandas.util.decorators import deprecate_kwarg
 
 def match(to_match, values, na_sentinel=-1):
     """
@@ -104,7 +105,7 @@ def factorize(values, sort=False, order=None, na_sentinel=-1):
         Sequence
     sort : boolean, default False
         Sort by values
-    order :
+    order : deprecated
     na_sentinel: int, default -1
         Value to mark "not found"
 
@@ -115,6 +116,10 @@ def factorize(values, sort=False, order=None, na_sentinel=-1):
 
     note: an array of Periods will ignore sort as it returns an always sorted PeriodIndex
     """
+    if order is not None:
+        warn("order is deprecated."
+             "See https://github.com/pydata/pandas/issues/6926", FutureWarning)
+
     from pandas.tseries.period import PeriodIndex
     vals = np.asarray(values)
     is_datetime = com.is_datetime64_dtype(vals)
diff --git a/pandas/tests/test_algos.py b/pandas/tests/test_algos.py
index ebc41ea457b52..07bf247e5aafe 100644
--- a/pandas/tests/test_algos.py
+++ b/pandas/tests/test_algos.py
@@ -47,6 +47,12 @@ def test_strings(self):
 class TestFactorize(tm.TestCase):
     _multiprocess_can_split_ = True
 
+    def test_warn(self):
+
+        s = Series([1, 2, 3])
+        with tm.assert_produces_warning(FutureWarning):
+            algos.factorize(s, order='A')
+
     def test_basic(self):
 
         labels, uniques = algos.factorize(['a', 'b', 'b', 'a',