From 0ec35317a2b924e8db5cf24b12f989c22ac59600 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Wed, 6 Jun 2018 19:22:37 -0400
Subject: [PATCH 01/22] Use of Enums in MultiIndex now supported

Due to an unnecessary "orderedness" check in `arrays/categorical.py`'s method `_factorize_from_iterable`, MultiIndex's constructor inappropriately threw a `TypeError` when passed an Enum as one of its iterables. This has been fixed.
---
 pandas/core/arrays/categorical.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/arrays/categorical.py b/pandas/core/arrays/categorical.py
index 30f9c56d24f02..8a7fab00179a9 100644
--- a/pandas/core/arrays/categorical.py
+++ b/pandas/core/arrays/categorical.py
@@ -2523,7 +2523,7 @@ def _factorize_from_iterable(values):
                                       ordered=values.ordered)
         codes = values.codes
     else:
-        cat = Categorical(values, ordered=True)
+        cat = Categorical(values, ordered=False)
         categories = cat.categories
         codes = cat.codes
     return codes, categories

From ca40575aa9ff44d7bddceee1c2c0a491fa5f5c03 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Wed, 6 Jun 2018 20:14:50 -0400
Subject: [PATCH 02/22] added a test for `MultiIndex` with `Enum`

---
 pandas/tests/indexes/test_multi.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index 0ab3447909d9b..d40857903ac79 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -3307,3 +3307,33 @@ def test_duplicate_multiindex_labels(self):
         with pytest.raises(ValueError):
             ind.set_levels([['A', 'B', 'A', 'A', 'B'], [2, 1, 3, -2, 5]],
                            inplace=True)
+    
+    def test_use_enum():
+        # GH 21298
+        # Allow use of Enums as one of the factors in a MultiIndex.
+        
+        # See https://github.com/pandas-dev/pandas/blob/0c65c57a279e755ab7093db925d1e580f9878dae
+        # /pandas/util/testing.py#L793-L799. We cannot simply use tm.assert_index_equal, as the
+        # "expected" index cannot actually be built yet.
+        from pandas.core.algorithms import take_1d
+        def _get_ilevel_values(index, level):
+            # accept level number only
+            unique = index.levels[level]
+            labels = index.labels[level]
+            filled = take_1d(unique.values, labels, fill_value=unique._na_value)
+            values = unique._shallow_copy(filled, name=index.names[level])
+            return values
+        
+        from enum import Enum
+        MyEnum = Enum("MyEnum", "A B")
+        df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[MyEnum, [1, 2]]))
+        exp_index_0 = pd.Index([MyEnum.A, MyEnum.A, MyEnum.B, MyEnum.B], dtype='object')
+        tm.assert_index_equal(_get_ilevel_values(df.columns, 0), exp_index_0)
+        
+        expected = df.copy()
+        df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"}, ignore_index=True)
+        expected.loc[0, [(MyEnum.A, 1), (MyEnum.B, 2)]] = 'abc', 'xyz'
+        tm.assert_frame_equal(df, expected)
+
+
+

From 38572290ffd1504bfc432451321f036de9548a0d Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Wed, 6 Jun 2018 20:15:46 -0400
Subject: [PATCH 03/22] Update test_multi.py

---
 pandas/tests/indexes/test_multi.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index d40857903ac79..6c03c5ecc23ac 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -3308,7 +3308,7 @@ def test_duplicate_multiindex_labels(self):
             ind.set_levels([['A', 'B', 'A', 'A', 'B'], [2, 1, 3, -2, 5]],
                            inplace=True)
     
-    def test_use_enum():
+    def test_use_enum_in_multiindex(self):
         # GH 21298
         # Allow use of Enums as one of the factors in a MultiIndex.
         

From 9aee04ab3b85554e07fa612644ae3e4e1d80379d Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Wed, 6 Jun 2018 20:28:23 -0400
Subject: [PATCH 04/22] PEP8

---
 pandas/tests/indexes/test_multi.py | 35 ++++++++++++++++++------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index 6c03c5ecc23ac..fbcd9ed9a3fd3 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -3307,33 +3307,40 @@ def test_duplicate_multiindex_labels(self):
         with pytest.raises(ValueError):
             ind.set_levels([['A', 'B', 'A', 'A', 'B'], [2, 1, 3, -2, 5]],
                            inplace=True)
-    
+
     def test_use_enum_in_multiindex(self):
         # GH 21298
         # Allow use of Enums as one of the factors in a MultiIndex.
-        
-        # See https://github.com/pandas-dev/pandas/blob/0c65c57a279e755ab7093db925d1e580f9878dae
-        # /pandas/util/testing.py#L793-L799. We cannot simply use tm.assert_index_equal, as the
-        # "expected" index cannot actually be built yet.
+
+        # See https://github.com/pandas-dev/pandas/blob/
+        # 0c65c57a279e755ab7093db925d1e580f9878dae/pandas/util/testing.py#L793-L799.
+        # We cannot simply use tm.assert_index_equal, as the "expected" index
+        # cannot actually be built yet.
         from pandas.core.algorithms import take_1d
+
         def _get_ilevel_values(index, level):
             # accept level number only
             unique = index.levels[level]
             labels = index.labels[level]
-            filled = take_1d(unique.values, labels, fill_value=unique._na_value)
+            filled = take_1d(
+                unique.values,
+                labels, fill_value=unique._na_value
+            )
             values = unique._shallow_copy(filled, name=index.names[level])
             return values
-        
+
         from enum import Enum
         MyEnum = Enum("MyEnum", "A B")
-        df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[MyEnum, [1, 2]]))
-        exp_index_0 = pd.Index([MyEnum.A, MyEnum.A, MyEnum.B, MyEnum.B], dtype='object')
+        df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
+            MyEnum,
+            [1, 2]
+        ]))
+        exp_index_0 = pd.Index([MyEnum.A, MyEnum.A, MyEnum.B, MyEnum.B],
+                               dtype='object')
         tm.assert_index_equal(_get_ilevel_values(df.columns, 0), exp_index_0)
-        
+
         expected = df.copy()
-        df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"}, ignore_index=True)
+        df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"},
+                       ignore_index=True)
         expected.loc[0, [(MyEnum.A, 1), (MyEnum.B, 2)]] = 'abc', 'xyz'
         tm.assert_frame_equal(df, expected)
-
-
-

From 60c8f2a741386f77e06aa49b6a515fe2bc2e7811 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 09:11:46 -0400
Subject: [PATCH 05/22] Put imports on top

---
 pandas/tests/indexes/test_multi.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index fbcd9ed9a3fd3..ee2aac30ae748 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -3311,13 +3311,13 @@ def test_duplicate_multiindex_labels(self):
     def test_use_enum_in_multiindex(self):
         # GH 21298
         # Allow use of Enums as one of the factors in a MultiIndex.
+        from enum import Enum
+        from pandas.core.algorithms import take_1d
 
         # See https://github.com/pandas-dev/pandas/blob/
         # 0c65c57a279e755ab7093db925d1e580f9878dae/pandas/util/testing.py#L793-L799.
         # We cannot simply use tm.assert_index_equal, as the "expected" index
         # cannot actually be built yet.
-        from pandas.core.algorithms import take_1d
-
         def _get_ilevel_values(index, level):
             # accept level number only
             unique = index.levels[level]
@@ -3329,7 +3329,6 @@ def _get_ilevel_values(index, level):
             values = unique._shallow_copy(filled, name=index.names[level])
             return values
 
-        from enum import Enum
         MyEnum = Enum("MyEnum", "A B")
         df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
             MyEnum,

From 13d67ca6af29792016f1fdca9fa6f0ab903b0faa Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 09:49:54 -0400
Subject: [PATCH 06/22] Update appveyor-27.yaml

---
 ci/appveyor-27.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/appveyor-27.yaml b/ci/appveyor-27.yaml
index cfc6a796bd77e..74527dfa34fed 100644
--- a/ci/appveyor-27.yaml
+++ b/ci/appveyor-27.yaml
@@ -27,3 +27,4 @@ dependencies:
   - pytest
   - pytest-xdist
   - moto
+  - enum34

From e6e66275ea028027c0f043ecbb6c9d7327db2cc4 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 09:50:45 -0400
Subject: [PATCH 07/22] Update circle-27-compat.yaml

---
 ci/circle-27-compat.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/circle-27-compat.yaml b/ci/circle-27-compat.yaml
index 81a48d4edf11c..a5c86a0ed2d2a 100644
--- a/ci/circle-27-compat.yaml
+++ b/ci/circle-27-compat.yaml
@@ -22,6 +22,7 @@ dependencies:
   # universal
   - pytest
   - pytest-xdist
+  - enum34
   - pip:
     - html5lib==1.0b2
     - beautifulsoup4==4.2.1

From d0607f448377ab49e926f899374ca10d16fdceaf Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 09:51:21 -0400
Subject: [PATCH 08/22] Update travis-27-locale.yaml

---
 ci/travis-27-locale.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/travis-27-locale.yaml b/ci/travis-27-locale.yaml
index 1312c1296d46a..9acc0bfd5353d 100644
--- a/ci/travis-27-locale.yaml
+++ b/ci/travis-27-locale.yaml
@@ -22,6 +22,7 @@ dependencies:
   # universal
   - pytest
   - pytest-xdist
+  - enum34
   - pip:
     - html5lib==1.0b2
     - beautifulsoup4==4.2.1

From ec5900a67dfe74ebfb2697fdf4c707a00ea959ea Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 09:51:53 -0400
Subject: [PATCH 09/22] Update travis-27.yaml

---
 ci/travis-27.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/travis-27.yaml b/ci/travis-27.yaml
index 22b993a2da886..eb16607dedf83 100644
--- a/ci/travis-27.yaml
+++ b/ci/travis-27.yaml
@@ -42,6 +42,7 @@ dependencies:
   - pytest
   - pytest-xdist
   - moto
+  - enum34
   - pip:
     - backports.lzma
     - cpplint

From 1c84176fb65335dbe09447fb9018212e1d676229 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 16:40:22 -0400
Subject: [PATCH 10/22] add whatsnew

---
 doc/source/whatsnew/v0.23.1.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index 9c29c34adb7dd..ed75007a27aa2 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -88,7 +88,7 @@ Indexing
 - Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
 - Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
--
+- Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
 
 I/O
 ^^^

From e914b2040195c8995f3312c665401866fe478f52 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 16:44:28 -0400
Subject: [PATCH 11/22] sync whatsnew with master

---
 doc/source/whatsnew/v0.23.1.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index ed75007a27aa2..490f5c4d77e69 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -88,6 +88,7 @@ Indexing
 - Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
 - Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
+- Bug in :attr:`DatetimeIndex.time` where given a tz-aware Timestamp, a tz-aware Time is returned instead of tz-naive  (:issue:`21267`)
 - Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
 
 I/O

From 5a55feee927356b924c6126f2798faac26e941c1 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 16:45:35 -0400
Subject: [PATCH 12/22] sync whatsnew with master

---
 doc/source/whatsnew/v0.23.1.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index 490f5c4d77e69..1a401a476074c 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -90,6 +90,7 @@ Indexing
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
 - Bug in :attr:`DatetimeIndex.time` where given a tz-aware Timestamp, a tz-aware Time is returned instead of tz-naive  (:issue:`21267`)
 - Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
+-
 
 I/O
 ^^^

From 191fe58efbd50899c1e278b02c042d1d564cf733 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 17:20:23 -0400
Subject: [PATCH 13/22] attempting to resolve conflict

---
 doc/source/whatsnew/v0.23.1.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index 1a401a476074c..9d5008da9f38d 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -79,13 +79,13 @@ Conversion
 
 -
 -
-
 Indexing
 ^^^^^^^^
 
 - Bug in :meth:`Series.reset_index` where appropriate error was not raised with an invalid level name (:issue:`20925`)
 - Bug in :func:`interval_range` when ``start``/``periods`` or ``end``/``periods`` are specified with float ``start`` or ``end`` (:issue:`21161`)
 - Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
+- Bug in :attr:`DatetimeIndex.date` where an incorrect date is returned when the input date has a non-UTC timezone (:issue:`21230`)
 - Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
 - Bug in :attr:`DatetimeIndex.time` where given a tz-aware Timestamp, a tz-aware Time is returned instead of tz-naive  (:issue:`21267`)

From bac47e2c6ca37199ff3ac4628b24f1d414b14e3d Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Thu, 7 Jun 2018 17:27:58 -0400
Subject: [PATCH 14/22] attempting to resolve conflicts in `whatsnew`

---
 doc/source/whatsnew/v0.23.1.txt | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index 9d5008da9f38d..d2a7dc633e6ec 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -79,16 +79,15 @@ Conversion
 
 -
 -
+
 Indexing
 ^^^^^^^^
 
 - Bug in :meth:`Series.reset_index` where appropriate error was not raised with an invalid level name (:issue:`20925`)
 - Bug in :func:`interval_range` when ``start``/``periods`` or ``end``/``periods`` are specified with float ``start`` or ``end`` (:issue:`21161`)
 - Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
-- Bug in :attr:`DatetimeIndex.date` where an incorrect date is returned when the input date has a non-UTC timezone (:issue:`21230`)
 - Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
-- Bug in :attr:`DatetimeIndex.time` where given a tz-aware Timestamp, a tz-aware Time is returned instead of tz-naive  (:issue:`21267`)
 - Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
 -
 

From f76d522392d7743e185dc3bb3c02f4d4c4920792 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Fri, 8 Jun 2018 08:35:58 -0400
Subject: [PATCH 15/22] remove whatsnew

---
 doc/source/whatsnew/v0.23.1.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/doc/source/whatsnew/v0.23.1.txt b/doc/source/whatsnew/v0.23.1.txt
index d2a7dc633e6ec..9c29c34adb7dd 100644
--- a/doc/source/whatsnew/v0.23.1.txt
+++ b/doc/source/whatsnew/v0.23.1.txt
@@ -88,7 +88,6 @@ Indexing
 - Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
 - Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
 - Bug in :meth:`MultiIndex.sort_index` which was not guaranteed to sort correctly with ``level=1``; this was also causing data misalignment in particular :meth:`DataFrame.stack` operations (:issue:`20994`, :issue:`20945`, :issue:`21052`)
-- Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
 -
 
 I/O

From 761a9d17a6e3d8f6562c503986b3087bdf07da28 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Fri, 8 Jun 2018 13:30:47 -0400
Subject: [PATCH 16/22] add to whatsnew 0.24

---
 doc/source/whatsnew/v0.24.0.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v0.24.0.txt b/doc/source/whatsnew/v0.24.0.txt
index c69de149a0f35..e09d162b7b00b 100644
--- a/doc/source/whatsnew/v0.24.0.txt
+++ b/doc/source/whatsnew/v0.24.0.txt
@@ -132,7 +132,7 @@ Strings
 Indexing
 ^^^^^^^^
 
--
+- Bug in :func:`pandas.core.arrays.categorical._factorize_from_iterable` inappropriately caused ``TypeError`` to be raised when an ``Enum`` was used as a factor in a ``MultiIndex`` (:issue:`21298`)
 -
 -
 

From 2e7921b3bab473bea1ca361d3cd22b1747eeeec9 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Fri, 8 Jun 2018 13:58:37 -0400
Subject: [PATCH 17/22] remove nested function from test

This nested function had been drawn directly from _within_ `pands.util.testing.assert_index_equal`. As there is no way to construct the target dataframe's (multi) index directly (hence this PR), I simply compare this index's _0th level_ to a manually constructed (simple) index. This comparison is given by a subroutine of `assert_index_equal` (which applies the subroutine to _each_ level).
---
 pandas/tests/indexes/test_multi.py | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index ee2aac30ae748..f004cbb9c51f0 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -3314,29 +3314,21 @@ def test_use_enum_in_multiindex(self):
         from enum import Enum
         from pandas.core.algorithms import take_1d
 
-        # See https://github.com/pandas-dev/pandas/blob/
-        # 0c65c57a279e755ab7093db925d1e580f9878dae/pandas/util/testing.py#L793-L799.
-        # We cannot simply use tm.assert_index_equal, as the "expected" index
-        # cannot actually be built yet.
-        def _get_ilevel_values(index, level):
-            # accept level number only
-            unique = index.levels[level]
-            labels = index.labels[level]
-            filled = take_1d(
-                unique.values,
-                labels, fill_value=unique._na_value
-            )
-            values = unique._shallow_copy(filled, name=index.names[level])
-            return values
-
         MyEnum = Enum("MyEnum", "A B")
         df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
             MyEnum,
             [1, 2]
         ]))
+
+        # cf. https://github.com/pandas-dev/pandas/blob/
+        # 0c65c57a279e755ab7093db925d1e580f9878dae/pandas/util/testing.py#L793-L799
+        unique = df.columns.levels[0]
+        labels = df.columns.labels[0]
+        filled = take_1d(unique.values, labels, fill_value=unique._na_value)
+        df_index_0 = unique._shallow_copy(filled, name=df.columns.names[0])
         exp_index_0 = pd.Index([MyEnum.A, MyEnum.A, MyEnum.B, MyEnum.B],
                                dtype='object')
-        tm.assert_index_equal(_get_ilevel_values(df.columns, 0), exp_index_0)
+        tm.assert_index_equal(df_index_0, exp_index_0)
 
         expected = df.copy()
         df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"},

From 21014c61ec6389ac84b67c6235fafb5184004d8c Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Fri, 8 Jun 2018 14:00:30 -0400
Subject: [PATCH 18/22] move imports to top

---
 pandas/tests/indexes/test_multi.py | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index f004cbb9c51f0..401afe2c211a9 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -5,7 +5,7 @@
 
 from datetime import timedelta
 from itertools import product
-
+from enum import Enum
 import pytest
 
 import numpy as np
@@ -20,6 +20,7 @@
 from pandas.core.indexes.base import InvalidIndexError
 from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 from pandas._libs.tslib import Timestamp
+from pandas.core.algorithms import take_1d
 
 import pandas.util.testing as tm
 
@@ -3311,9 +3312,6 @@ def test_duplicate_multiindex_labels(self):
     def test_use_enum_in_multiindex(self):
         # GH 21298
         # Allow use of Enums as one of the factors in a MultiIndex.
-        from enum import Enum
-        from pandas.core.algorithms import take_1d
-
         MyEnum = Enum("MyEnum", "A B")
         df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
             MyEnum,

From 4cd2dff96775a828687acd7c65919ec135824cf4 Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Tue, 19 Jun 2018 13:24:05 -0400
Subject: [PATCH 19/22] jreback fixes

---
 ci/appveyor-27.yaml                |  2 +-
 ci/circle-27-compat.yaml           |  1 -
 ci/travis-27-locale.yaml           |  1 -
 pandas/tests/indexes/test_multi.py | 15 ++++-----------
 4 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/ci/appveyor-27.yaml b/ci/appveyor-27.yaml
index 74527dfa34fed..cf44bba9a3937 100644
--- a/ci/appveyor-27.yaml
+++ b/ci/appveyor-27.yaml
@@ -27,4 +27,4 @@ dependencies:
   - pytest
   - pytest-xdist
   - moto
-  - enum34
+
diff --git a/ci/circle-27-compat.yaml b/ci/circle-27-compat.yaml
index a5c86a0ed2d2a..81a48d4edf11c 100644
--- a/ci/circle-27-compat.yaml
+++ b/ci/circle-27-compat.yaml
@@ -22,7 +22,6 @@ dependencies:
   # universal
   - pytest
   - pytest-xdist
-  - enum34
   - pip:
     - html5lib==1.0b2
     - beautifulsoup4==4.2.1
diff --git a/ci/travis-27-locale.yaml b/ci/travis-27-locale.yaml
index 9acc0bfd5353d..1312c1296d46a 100644
--- a/ci/travis-27-locale.yaml
+++ b/ci/travis-27-locale.yaml
@@ -22,7 +22,6 @@ dependencies:
   # universal
   - pytest
   - pytest-xdist
-  - enum34
   - pip:
     - html5lib==1.0b2
     - beautifulsoup4==4.2.1
diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index 401afe2c211a9..f23a24a28b364 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -5,7 +5,6 @@
 
 from datetime import timedelta
 from itertools import product
-from enum import Enum
 import pytest
 
 import numpy as np
@@ -20,7 +19,6 @@
 from pandas.core.indexes.base import InvalidIndexError
 from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 from pandas._libs.tslib import Timestamp
-from pandas.core.algorithms import take_1d
 
 import pandas.util.testing as tm
 
@@ -3309,24 +3307,19 @@ def test_duplicate_multiindex_labels(self):
             ind.set_levels([['A', 'B', 'A', 'A', 'B'], [2, 1, 3, -2, 5]],
                            inplace=True)
 
+    @td.skip_if_no('enum')
     def test_use_enum_in_multiindex(self):
         # GH 21298
         # Allow use of Enums as one of the factors in a MultiIndex.
+        from enum import Enum
         MyEnum = Enum("MyEnum", "A B")
         df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
             MyEnum,
             [1, 2]
         ]))
 
-        # cf. https://github.com/pandas-dev/pandas/blob/
-        # 0c65c57a279e755ab7093db925d1e580f9878dae/pandas/util/testing.py#L793-L799
-        unique = df.columns.levels[0]
-        labels = df.columns.labels[0]
-        filled = take_1d(unique.values, labels, fill_value=unique._na_value)
-        df_index_0 = unique._shallow_copy(filled, name=df.columns.names[0])
-        exp_index_0 = pd.Index([MyEnum.A, MyEnum.A, MyEnum.B, MyEnum.B],
-                               dtype='object')
-        tm.assert_index_equal(df_index_0, exp_index_0)
+        exp_index_0 = pd.Index([MyEnum.A, MyEnum.B], dtype='object')
+        tm.assert_index_equal(df.columns.levels[0], exp_index_0)
 
         expected = df.copy()
         df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"},

From 702594b13acf3e89f6540fc77cbcd4364621be8f Mon Sep 17 00:00:00 2001
From: Benjamin Diamond <30356252+benediamond@users.noreply.github.com>
Date: Sun, 12 Aug 2018 16:29:27 -0400
Subject: [PATCH 20/22] import pandas.util._test_decorators as td

---
 pandas/tests/indexes/test_multi.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/tests/indexes/test_multi.py b/pandas/tests/indexes/test_multi.py
index f23a24a28b364..ae26c4bec4da0 100644
--- a/pandas/tests/indexes/test_multi.py
+++ b/pandas/tests/indexes/test_multi.py
@@ -21,6 +21,7 @@
 from pandas._libs.tslib import Timestamp
 
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 from pandas.util.testing import assert_almost_equal, assert_copy
 

From 6e4485f1660924904eda5f65c91c7701fe59d1bf Mon Sep 17 00:00:00 2001
From: benediamond <benjamin@dreyzen.com>
Date: Thu, 22 Nov 2018 00:10:24 -0500
Subject: [PATCH 21/22] added test

---
 pandas/tests/indexes/multi/test_enum.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 pandas/tests/indexes/multi/test_enum.py

diff --git a/pandas/tests/indexes/multi/test_enum.py b/pandas/tests/indexes/multi/test_enum.py
new file mode 100644
index 0000000000000..3fec4fa049be2
--- /dev/null
+++ b/pandas/tests/indexes/multi/test_enum.py
@@ -0,0 +1,25 @@
+import pandas as pd
+
+import pandas.util.testing as tm
+import pandas.util._test_decorators as td
+
+
+@td.skip_if_no('enum')
+def test_enum_in_multiindex(self):
+    # GH 21298
+    # Allow use of Enums as one of the factors in a MultiIndex.
+    from enum import Enum
+    MyEnum = Enum("MyEnum", "A B")
+    df = pd.DataFrame(columns=pd.MultiIndex.from_product(iterables=[
+        MyEnum,
+        [1, 2]
+    ]))
+
+    exp_index_0 = pd.Index([MyEnum.A, MyEnum.B], dtype='object')
+    tm.assert_index_equal(df.columns.levels[0], exp_index_0)
+
+    expected = df.copy()
+    df = df.append({(MyEnum.A, 1): "abc", (MyEnum.B, 2): "xyz"},
+                   ignore_index=True)
+    expected.loc[0, [(MyEnum.A, 1), (MyEnum.B, 2)]] = 'abc', 'xyz'
+    tm.assert_frame_equal(df, expected)

From 06437cdf0c4f2bc388f165dced8cd9cbcc6d02d2 Mon Sep 17 00:00:00 2001
From: benediamond <benjamin@dreyzen.com>
Date: Thu, 22 Nov 2018 10:46:30 -0500
Subject: [PATCH 22/22] typo: remove 'self'

---
 pandas/tests/indexes/multi/test_enum.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/indexes/multi/test_enum.py b/pandas/tests/indexes/multi/test_enum.py
index 3fec4fa049be2..a13dd465ca813 100644
--- a/pandas/tests/indexes/multi/test_enum.py
+++ b/pandas/tests/indexes/multi/test_enum.py
@@ -5,7 +5,7 @@
 
 
 @td.skip_if_no('enum')
-def test_enum_in_multiindex(self):
+def test_enum_in_multiindex():
     # GH 21298
     # Allow use of Enums as one of the factors in a MultiIndex.
     from enum import Enum