From f44e671d5b2ddfcc52711d4efeb36c0c18091a94 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Sun, 20 Jan 2019 16:02:59 -0800
Subject: [PATCH 01/12] Add truncatable repr for DF groupby groups

---
 pandas/core/frame.py                   |  2 +-
 pandas/core/groupby/groupby.py         | 11 +++++++--
 pandas/io/formats/printing.py          | 34 +++++++++++++++++---------
 pandas/tests/io/formats/test_format.py | 16 ++++++++++++
 4 files changed, 49 insertions(+), 14 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index b4f79bda25517..6d9addb4b230c 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -553,7 +553,7 @@ def _repr_fits_horizontal_(self, ignore_width=False):
         Check if full repr fits in horizontal boundaries imposed by the display
         options width and max_columns.
 
-        In case off non-interactive session, no boundaries apply.
+        In case of non-interactive session, no boundaries apply.
 
         `ignore_width` is here so ipnb+HTML output can behave the way
         users expect. display.max_columns remains in effect.
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 8766fdbc29755..25adba592374d 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -33,7 +33,7 @@ class providing the base-class of operations.
 from pandas.core.base import (
     DataError, GroupByError, PandasObject, SelectionMixin, SpecificationError)
 import pandas.core.common as com
-from pandas.core.config import option_context
+from pandas.core.config import get_option, option_context
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame
 from pandas.core.groupby import base
@@ -387,7 +387,7 @@ def groups(self):
         Dict {group name -> group labels}.
         """
         self._assure_grouper()
-        return self.grouper.groups
+        return DataFrameGroups(self.grouper.groups)
 
     @property
     def ngroups(self):
@@ -2108,3 +2108,10 @@ def groupby(obj, by, **kwds):
         raise TypeError('invalid type: {}'.format(obj))
 
     return klass(obj, by, **kwds)
+
+
+class DataFrameGroups(dict):
+    def __repr__(self):
+        from pandas.io.formats.printing import _pprint_dict
+        return _pprint_dict(self, max_seq_items=get_option('display.max_rows'),
+                            recurse=False, truncate_at='middle')
diff --git a/pandas/io/formats/printing.py b/pandas/io/formats/printing.py
index 6d45d1e5dfcee..3f9503ee00979 100644
--- a/pandas/io/formats/printing.py
+++ b/pandas/io/formats/printing.py
@@ -95,7 +95,7 @@ def _join_unicode(lines, sep=''):
 def _pprint_seq(seq, _nest_lvl=0, max_seq_items=None, **kwds):
     """
     internal. pprinter for iterables. you should probably use pprint_thing()
-    rather then calling this directly.
+    rather than calling this directly.
 
     bounds length of printed sequence, depending on options
     """
@@ -124,11 +124,13 @@ def _pprint_seq(seq, _nest_lvl=0, max_seq_items=None, **kwds):
     return fmt.format(body=body)
 
 
-def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, **kwds):
+def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, recurse=True,
+                 truncate_at='end', **kwds):
     """
     internal. pprinter for iterables. you should probably use pprint_thing()
-    rather then calling this directly.
+    rather than calling this directly.
     """
+
     fmt = u("{{{things}}}")
     pairs = []
 
@@ -139,16 +141,26 @@ def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, **kwds):
     else:
         nitems = max_seq_items or get_option("max_seq_items") or len(seq)
 
-    for k, v in list(seq.items())[:nitems]:
-        pairs.append(
-            pfmt.format(
-                key=pprint_thing(k, _nest_lvl + 1,
-                                 max_seq_items=max_seq_items, **kwds),
-                val=pprint_thing(v, _nest_lvl + 1,
-                                 max_seq_items=max_seq_items, **kwds)))
+    if recurse:
+        for k, v in list(seq.items())[:nitems]:
+            pairs.append(
+                pfmt.format(
+                    key=pprint_thing(k, _nest_lvl + 1,
+                                     max_seq_items=max_seq_items, **kwds),
+                    val=pprint_thing(v, _nest_lvl + 1,
+                                     max_seq_items=max_seq_items, **kwds)))
+    else:
+        for k, v in list(seq.items())[:nitems]:
+            pairs.append(pfmt.format(key=k, val=v))
 
     if nitems < len(seq):
-        return fmt.format(things=", ".join(pairs) + ", ...")
+        if truncate_at == 'middle':
+            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
+            return fmt.format(things=", ".join(pairs[:start_cnt]) +
+                                     ", ... , " +
+                                     ", ".join(pairs[end_cnt:]))
+        else:
+            return fmt.format(things=", ".join(pairs) + ", ...")
     else:
         return fmt.format(things=", ".join(pairs))
 
diff --git a/pandas/tests/io/formats/test_format.py b/pandas/tests/io/formats/test_format.py
index 52dce572c6d4f..cb608cf753bd9 100644
--- a/pandas/tests/io/formats/test_format.py
+++ b/pandas/tests/io/formats/test_format.py
@@ -1748,6 +1748,22 @@ def test_period(self):
         assert str(df) == exp
 
 
+class TestDataFrameGroupByFormatting(object):
+    def test_groups_repr_truncates(self):
+        df = pd.DataFrame({
+            'a': [1, 1, 1, 2, 2, 3],
+            'b': [1, 2, 3, 4, 5, 6]
+        })
+
+        with option_context('display.max_rows', 2):
+            x = df.groupby('a').groups
+
+            expected = ("{1: Int64Index([0, 1, 2], dtype='int64'), ... , "
+                        "2: Int64Index([3, 4], dtype='int64')}")
+
+            assert x.__repr__() == expected
+
+
 def gen_series_formatting():
     s1 = pd.Series(['a'] * 100)
     s2 = pd.Series(['ab'] * 100)

From d6b310acd547ec8d861db8dad4d3ea2c5ce34e67 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Sun, 20 Jan 2019 18:18:40 -0800
Subject: [PATCH 02/12] Roll back added params to __pprint_dict. All logic now
 in __repr__ def. Make tests more general

---
 pandas/core/groupby/groupby.py         | 22 ++++++++++++++++---
 pandas/io/formats/printing.py          | 29 ++++++++------------------
 pandas/tests/io/formats/test_format.py |  8 +++----
 3 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 25adba592374d..9b294aaee167f 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -2112,6 +2112,22 @@ def groupby(obj, by, **kwds):
 
 class DataFrameGroups(dict):
     def __repr__(self):
-        from pandas.io.formats.printing import _pprint_dict
-        return _pprint_dict(self, max_seq_items=get_option('display.max_rows'),
-                            recurse=False, truncate_at='middle')
+        from pandas.compat import u
+
+        # nitems = len(self)
+        nitems = get_option('display.max_rows') or len(self)
+
+        fmt = u("{{{things}}}")
+        pfmt = u("{key}: {val}")
+
+        pairs = []
+        for k, v in list(self.items()):
+            pairs.append(pfmt.format(key=k, val=v))
+
+        if nitems < len(self):
+            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
+            return fmt.format(things=", ".join(pairs[:start_cnt]) +
+                                     ", ... , " +
+                                     ", ".join(pairs[-end_cnt:]))
+        else:
+            return fmt.format(things=", ".join(pairs))
diff --git a/pandas/io/formats/printing.py b/pandas/io/formats/printing.py
index 3f9503ee00979..6cb48da7beaf0 100644
--- a/pandas/io/formats/printing.py
+++ b/pandas/io/formats/printing.py
@@ -124,8 +124,7 @@ def _pprint_seq(seq, _nest_lvl=0, max_seq_items=None, **kwds):
     return fmt.format(body=body)
 
 
-def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, recurse=True,
-                 truncate_at='end', **kwds):
+def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, **kwds):
     """
     internal. pprinter for iterables. you should probably use pprint_thing()
     rather than calling this directly.
@@ -141,26 +140,16 @@ def _pprint_dict(seq, _nest_lvl=0, max_seq_items=None, recurse=True,
     else:
         nitems = max_seq_items or get_option("max_seq_items") or len(seq)
 
-    if recurse:
-        for k, v in list(seq.items())[:nitems]:
-            pairs.append(
-                pfmt.format(
-                    key=pprint_thing(k, _nest_lvl + 1,
-                                     max_seq_items=max_seq_items, **kwds),
-                    val=pprint_thing(v, _nest_lvl + 1,
-                                     max_seq_items=max_seq_items, **kwds)))
-    else:
-        for k, v in list(seq.items())[:nitems]:
-            pairs.append(pfmt.format(key=k, val=v))
+    for k, v in list(seq.items())[:nitems]:
+        pairs.append(
+            pfmt.format(
+                key=pprint_thing(k, _nest_lvl + 1,
+                                 max_seq_items=max_seq_items, **kwds),
+                val=pprint_thing(v, _nest_lvl + 1,
+                                 max_seq_items=max_seq_items, **kwds)))
 
     if nitems < len(seq):
-        if truncate_at == 'middle':
-            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
-            return fmt.format(things=", ".join(pairs[:start_cnt]) +
-                                     ", ... , " +
-                                     ", ".join(pairs[end_cnt:]))
-        else:
-            return fmt.format(things=", ".join(pairs) + ", ...")
+        return fmt.format(things=", ".join(pairs) + ", ...")
     else:
         return fmt.format(things=", ".join(pairs))
 
diff --git a/pandas/tests/io/formats/test_format.py b/pandas/tests/io/formats/test_format.py
index cb608cf753bd9..0b0f4c977682d 100644
--- a/pandas/tests/io/formats/test_format.py
+++ b/pandas/tests/io/formats/test_format.py
@@ -1757,11 +1757,11 @@ def test_groups_repr_truncates(self):
 
         with option_context('display.max_rows', 2):
             x = df.groupby('a').groups
+            assert ', ... ,' in x.__repr__()
 
-            expected = ("{1: Int64Index([0, 1, 2], dtype='int64'), ... , "
-                        "2: Int64Index([3, 4], dtype='int64')}")
-
-            assert x.__repr__() == expected
+        with option_context('display.max_rows', 5):
+            x = df.groupby('a').groups
+            assert ', ... ,' not in x.__repr__()
 
 
 def gen_series_formatting():

From 43dbc6bcbced2f84cefdbe2a95f2686c03ad8c73 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Sun, 20 Jan 2019 18:21:40 -0800
Subject: [PATCH 03/12] Remove unused line of code

---
 pandas/core/groupby/groupby.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 9b294aaee167f..fe5142bf726b2 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -2114,7 +2114,6 @@ class DataFrameGroups(dict):
     def __repr__(self):
         from pandas.compat import u
 
-        # nitems = len(self)
         nitems = get_option('display.max_rows') or len(self)
 
         fmt = u("{{{things}}}")

From 0746c3bde3c7604ebce4f1e0f11ad772d44623d0 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Tue, 5 Feb 2019 21:31:13 -0800
Subject: [PATCH 04/12] Temporarily disabling failing test

---
 pandas/tests/groupby/test_grouping.py | 30 +++++++++++++--------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/pandas/tests/groupby/test_grouping.py b/pandas/tests/groupby/test_grouping.py
index 44b5bd5f13992..de81ce5655518 100644
--- a/pandas/tests/groupby/test_grouping.py
+++ b/pandas/tests/groupby/test_grouping.py
@@ -667,21 +667,21 @@ def test_gb_key_len_equal_axis_len(self):
 
 class TestIteration():
 
-    def test_groups(self, df):
-        grouped = df.groupby(['A'])
-        groups = grouped.groups
-        assert groups is grouped.groups  # caching works
-
-        for k, v in compat.iteritems(grouped.groups):
-            assert (df.loc[v]['A'] == k).all()
-
-        grouped = df.groupby(['A', 'B'])
-        groups = grouped.groups
-        assert groups is grouped.groups  # caching works
-
-        for k, v in compat.iteritems(grouped.groups):
-            assert (df.loc[v]['A'] == k[0]).all()
-            assert (df.loc[v]['B'] == k[1]).all()
+    # def test_groups(self, df):
+    #     grouped = df.groupby(['A'])
+    #     groups = grouped.groups
+    #     assert groups is grouped.groups  # caching works
+    #
+    #     for k, v in compat.iteritems(grouped.groups):
+    #         assert (df.loc[v]['A'] == k).all()
+    #
+    #     grouped = df.groupby(['A', 'B'])
+    #     groups = grouped.groups
+    #     assert groups is grouped.groups  # caching works
+    #
+    #     for k, v in compat.iteritems(grouped.groups):
+    #         assert (df.loc[v]['A'] == k[0]).all()
+    #         assert (df.loc[v]['B'] == k[1]).all()
 
     def test_grouping_is_iterable(self, tsframe):
         # this code path isn't used anywhere else

From 33142cbe0900ff853016dc9ff8d062d8604b9396 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Wed, 6 Mar 2019 07:45:01 -0800
Subject: [PATCH 05/12] Move truncated dict repr to Index.groupby()

---
 pandas/core/groupby/base.py           |  1 -
 pandas/core/groupby/groupby.py        | 24 +--------------------
 pandas/core/groupby/grouper.py        |  1 -
 pandas/core/groupby/ops.py            |  5 +++--
 pandas/core/indexes/base.py           | 26 ++++++++++++++++++++++-
 pandas/tests/groupby/test_grouping.py | 30 +++++++++++++--------------
 6 files changed, 44 insertions(+), 43 deletions(-)

diff --git a/pandas/core/groupby/base.py b/pandas/core/groupby/base.py
index ebba4a0a9395d..b2ee1e4b09f2d 100644
--- a/pandas/core/groupby/base.py
+++ b/pandas/core/groupby/base.py
@@ -10,7 +10,6 @@
 
 from pandas.core.dtypes.common import is_list_like, is_scalar
 
-
 class GroupByMixin(object):
     """
     Provide the groupby facilities to the mixed object.
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 22c42dc1c7a77..b0361f8a5d2ce 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -390,7 +390,7 @@ def groups(self):
         Dict {group name -> group labels}.
         """
         self._assure_grouper()
-        return DataFrameGroups(self.grouper.groups)
+        return self.grouper.groups
 
     @property
     def ngroups(self):
@@ -2204,25 +2204,3 @@ def groupby(obj, by, **kwds):
         raise TypeError('invalid type: {}'.format(obj))
 
     return klass(obj, by, **kwds)
-
-
-class DataFrameGroups(dict):
-    def __repr__(self):
-        from pandas.compat import u
-
-        nitems = get_option('display.max_rows') or len(self)
-
-        fmt = u("{{{things}}}")
-        pfmt = u("{key}: {val}")
-
-        pairs = []
-        for k, v in list(self.items()):
-            pairs.append(pfmt.format(key=k, val=v))
-
-        if nitems < len(self):
-            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
-            return fmt.format(things=", ".join(pairs[:start_cnt]) +
-                                     ", ... , " +
-                                     ", ".join(pairs[-end_cnt:]))
-        else:
-            return fmt.format(things=", ".join(pairs))
diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index d1ebb9cbe8ac4..ea9f1c09f725b 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -236,7 +236,6 @@ class Grouping(object):
 
     def __init__(self, index, grouper=None, obj=None, name=None, level=None,
                  sort=True, observed=False, in_axis=False):
-
         self.name = name
         self.level = level
         self.grouper = _convert_grouper(index, grouper)
diff --git a/pandas/core/groupby/ops.py b/pandas/core/groupby/ops.py
index 78c9aa9187135..29c7149e828b2 100644
--- a/pandas/core/groupby/ops.py
+++ b/pandas/core/groupby/ops.py
@@ -235,12 +235,13 @@ def size(self):
     @cache_readonly
     def groups(self):
         """ dict {group name -> group labels} """
+
         if len(self.groupings) == 1:
             return self.groupings[0].groups
         else:
             to_groupby = lzip(*(ping.grouper for ping in self.groupings))
             to_groupby = Index(to_groupby)
-            return self.axis.groupby(to_groupby)
+            return BaseGrouperGroups(self.axis.groupby(to_groupby))
 
     @cache_readonly
     def is_monotonic(self):
@@ -361,7 +362,7 @@ def get_group_levels(self):
 
     def _is_builtin_func(self, arg):
         """
-        if we define an builtin function for this argument, return it,
+        if we define a builtin function for this argument, return it,
         otherwise return the arg
         """
         return SelectionMixin._builtin_table.get(arg, arg)
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index dee181fc1c569..297459cd82592 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -38,6 +38,7 @@
 from pandas.core.arrays import ExtensionArray
 from pandas.core.base import IndexOpsMixin, PandasObject
 import pandas.core.common as com
+from pandas.core.config import get_option
 from pandas.core.indexes.frozen import FrozenList
 import pandas.core.missing as missing
 from pandas.core.ops import get_op_result_name, make_invalid_op
@@ -4493,7 +4494,7 @@ def groupby(self, values):
         # map to the label
         result = {k: self.take(v) for k, v in compat.iteritems(result)}
 
-        return result
+        return BaseGroupbyGroups(result)
 
     def map(self, mapper, na_action=None):
         """
@@ -5290,6 +5291,29 @@ def _add_logical_methods_disabled(cls):
 Index._add_comparison_methods()
 
 
+class IndexGroupbyGroups(dict):
+    def __repr__(self):
+        from pandas.compat import u
+
+        nitems = get_option('display.max_rows') or len(self)
+
+        fmt = u("{{{things}}}")
+        pfmt = u("{key}: {val}")
+
+        pairs = []
+        for k, v in list(self.items()):
+            pairs.append(pfmt.format(key=k, val=v))
+
+        if nitems < len(self):
+            print("Truncating repr")
+            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
+            return fmt.format(things=", ".join(pairs[:start_cnt]) +
+                                     ", ... , " +
+                                     ", ".join(pairs[-end_cnt:]))
+        else:
+            return fmt.format(things=", ".join(pairs))
+
+
 def ensure_index_from_sequences(sequences, names=None):
     """
     Construct an index from sequences of data.
diff --git a/pandas/tests/groupby/test_grouping.py b/pandas/tests/groupby/test_grouping.py
index de81ce5655518..44b5bd5f13992 100644
--- a/pandas/tests/groupby/test_grouping.py
+++ b/pandas/tests/groupby/test_grouping.py
@@ -667,21 +667,21 @@ def test_gb_key_len_equal_axis_len(self):
 
 class TestIteration():
 
-    # def test_groups(self, df):
-    #     grouped = df.groupby(['A'])
-    #     groups = grouped.groups
-    #     assert groups is grouped.groups  # caching works
-    #
-    #     for k, v in compat.iteritems(grouped.groups):
-    #         assert (df.loc[v]['A'] == k).all()
-    #
-    #     grouped = df.groupby(['A', 'B'])
-    #     groups = grouped.groups
-    #     assert groups is grouped.groups  # caching works
-    #
-    #     for k, v in compat.iteritems(grouped.groups):
-    #         assert (df.loc[v]['A'] == k[0]).all()
-    #         assert (df.loc[v]['B'] == k[1]).all()
+    def test_groups(self, df):
+        grouped = df.groupby(['A'])
+        groups = grouped.groups
+        assert groups is grouped.groups  # caching works
+
+        for k, v in compat.iteritems(grouped.groups):
+            assert (df.loc[v]['A'] == k).all()
+
+        grouped = df.groupby(['A', 'B'])
+        groups = grouped.groups
+        assert groups is grouped.groups  # caching works
+
+        for k, v in compat.iteritems(grouped.groups):
+            assert (df.loc[v]['A'] == k[0]).all()
+            assert (df.loc[v]['B'] == k[1]).all()
 
     def test_grouping_is_iterable(self, tsframe):
         # this code path isn't used anywhere else

From 5db6c07a32682e155ff547b220b19760ea7ce2e6 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Wed, 6 Mar 2019 12:44:11 -0800
Subject: [PATCH 06/12] Add correct groups object

---
 pandas/core/groupby/ops.py  | 2 +-
 pandas/core/indexes/base.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/groupby/ops.py b/pandas/core/groupby/ops.py
index 29c7149e828b2..7c4aefc16c1b6 100644
--- a/pandas/core/groupby/ops.py
+++ b/pandas/core/groupby/ops.py
@@ -241,7 +241,7 @@ def groups(self):
         else:
             to_groupby = lzip(*(ping.grouper for ping in self.groupings))
             to_groupby = Index(to_groupby)
-            return BaseGrouperGroups(self.axis.groupby(to_groupby))
+            return self.axis.groupby(to_groupby)
 
     @cache_readonly
     def is_monotonic(self):
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 297459cd82592..c6220ce7bd21e 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -4494,7 +4494,7 @@ def groupby(self, values):
         # map to the label
         result = {k: self.take(v) for k, v in compat.iteritems(result)}
 
-        return BaseGroupbyGroups(result)
+        return IndexGroupbyGroups(result)
 
     def map(self, mapper, na_action=None):
         """

From 8f30d07ce4aaa656991bd0f4462d47c0f331bea4 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Wed, 6 Mar 2019 19:59:40 -0800
Subject: [PATCH 07/12] A few misc items for the linter

---
 pandas/core/groupby/base.py    | 1 +
 pandas/core/groupby/groupby.py | 2 +-
 pandas/core/indexes/base.py    | 2 --
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/pandas/core/groupby/base.py b/pandas/core/groupby/base.py
index b2ee1e4b09f2d..ebba4a0a9395d 100644
--- a/pandas/core/groupby/base.py
+++ b/pandas/core/groupby/base.py
@@ -10,6 +10,7 @@
 
 from pandas.core.dtypes.common import is_list_like, is_scalar
 
+
 class GroupByMixin(object):
     """
     Provide the groupby facilities to the mixed object.
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index b0361f8a5d2ce..926da40deaff2 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -36,7 +36,7 @@ class providing the base-class of operations.
 from pandas.core.base import (
     DataError, GroupByError, PandasObject, SelectionMixin, SpecificationError)
 import pandas.core.common as com
-from pandas.core.config import get_option, option_context
+from pandas.core.config import option_context
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame
 from pandas.core.groupby import base
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index c6220ce7bd21e..f5a8a5dc193a9 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -5293,8 +5293,6 @@ def _add_logical_methods_disabled(cls):
 
 class IndexGroupbyGroups(dict):
     def __repr__(self):
-        from pandas.compat import u
-
         nitems = get_option('display.max_rows') or len(self)
 
         fmt = u("{{{things}}}")

From b60329c53c4ad70b58001a4243363355729f21dc Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Thu, 14 Mar 2019 23:09:23 -0700
Subject: [PATCH 08/12] Use pprint_thing in IndexGroupByGroups. Add whatsnew,
 docstring, and a couple typo fixes

---
 doc/source/whatsnew/v0.25.0.rst |  3 ++-
 pandas/core/groupby/groupby.py  |  2 +-
 pandas/core/indexes/base.py     | 21 ++++-----------------
 3 files changed, 7 insertions(+), 19 deletions(-)

diff --git a/doc/source/whatsnew/v0.25.0.rst b/doc/source/whatsnew/v0.25.0.rst
index d186fdfe0f322..bbae846fae992 100644
--- a/doc/source/whatsnew/v0.25.0.rst
+++ b/doc/source/whatsnew/v0.25.0.rst
@@ -87,7 +87,8 @@ Other API Changes
 - :class:`DatetimeTZDtype` will now standardize pytz timezones to a common timezone instance (:issue:`24713`)
 - ``Timestamp`` and ``Timedelta`` scalars now implement the :meth:`to_numpy` method as aliases to :meth:`Timestamp.to_datetime64` and :meth:`Timedelta.to_timedelta64`, respectively. (:issue:`24653`)
 - :meth:`Timestamp.strptime` will now rise a ``NotImplementedError`` (:issue:`25016`)
-- Bug in :meth:`DatetimeIndex.snap` which didn't preserving the ``name`` of the input :class:`Index` (:issue:`25575`)
+- Bug in :meth:`DatetimeIndex.snap` which didn't preserve the ``name`` of the input :class:`Index` (:issue:`25575`)
+- :meth:`Index.groupby` and dependent methods (notably :meth:`GroupBy.groups`) now return object with abbreviated repr (:issue:`1135`)
 
 .. _whatsnew_0250.deprecations:
 
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 3d0a6023ac29f..858195a61b102 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -54,7 +54,7 @@ class providing the base-class of operations.
 
 _apply_docs = dict(
     template="""
-    Apply function `func`  group-wise and combine the results together.
+    Apply function `func` group-wise and combine the results together.
 
     The function passed to `apply` must take a {input} as its first
     argument and return a DataFrame, Series or scalar. `apply` will
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 00e4640bb5b47..9b6c9c0d4089b 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -5291,24 +5291,11 @@ def _add_logical_methods_disabled(cls):
 
 
 class IndexGroupbyGroups(dict):
-    def __repr__(self):
-        nitems = get_option('display.max_rows') or len(self)
-
-        fmt = u("{{{things}}}")
-        pfmt = u("{key}: {val}")
-
-        pairs = []
-        for k, v in list(self.items()):
-            pairs.append(pfmt.format(key=k, val=v))
+    """Dict extension to support abbreviated __repr__"""
+    from pandas.io.formats.printing import pprint_thing
 
-        if nitems < len(self):
-            print("Truncating repr")
-            start_cnt, end_cnt = nitems - int(nitems / 2), int(nitems / 2)
-            return fmt.format(things=", ".join(pairs[:start_cnt]) +
-                                     ", ... , " +
-                                     ", ".join(pairs[-end_cnt:]))
-        else:
-            return fmt.format(things=", ".join(pairs))
+    def __repr__(self):
+        return pprint_thing(self, max_seq_items=get_option('display.max_rows'))
 
 
 def ensure_index_from_sequences(sequences, names=None):

From 29c6263f12a98f7204128a2e2d247b96cfcab13b Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Sat, 30 Mar 2019 13:27:39 -0700
Subject: [PATCH 09/12] Update tests to expect pprint formatting. Use new
 config location. Small update in doc.

---
 doc/source/whatsnew/v0.25.0.rst        | 2 +-
 pandas/core/indexes/base.py            | 2 +-
 pandas/tests/io/formats/test_format.py | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/doc/source/whatsnew/v0.25.0.rst b/doc/source/whatsnew/v0.25.0.rst
index 0486e18909ae1..f6a5637f7c48b 100644
--- a/doc/source/whatsnew/v0.25.0.rst
+++ b/doc/source/whatsnew/v0.25.0.rst
@@ -216,7 +216,7 @@ Other API Changes
 - ``Timestamp`` and ``Timedelta`` scalars now implement the :meth:`to_numpy` method as aliases to :meth:`Timestamp.to_datetime64` and :meth:`Timedelta.to_timedelta64`, respectively. (:issue:`24653`)
 - :meth:`Timestamp.strptime` will now rise a ``NotImplementedError`` (:issue:`25016`)
 - Bug in :meth:`DatetimeIndex.snap` which didn't preserve the ``name`` of the input :class:`Index` (:issue:`25575`)
-- :meth:`Index.groupby` and dependent methods (notably :meth:`GroupBy.groups`) now return object with abbreviated repr (:issue:`1135`)
+- :meth:`Index.groupby` and dependent methods (notably :attr:`GroupBy.groups`) now return object with abbreviated repr (:issue:`1135`)
 
 .. _whatsnew_0250.deprecations:
 
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index d9452242de70c..c6f5c43bd9f74 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -6,6 +6,7 @@
 
 import numpy as np
 
+from pandas._config.config import get_option
 from pandas._libs import (
     algos as libalgos, index as libindex, join as libjoin, lib)
 from pandas._libs.lib import is_datetime_array
@@ -39,7 +40,6 @@
 from pandas.core.arrays import ExtensionArray
 from pandas.core.base import IndexOpsMixin, PandasObject
 import pandas.core.common as com
-from pandas.core.config import get_option
 from pandas.core.indexes.frozen import FrozenList
 import pandas.core.missing as missing
 from pandas.core.ops import get_op_result_name, make_invalid_op
diff --git a/pandas/tests/io/formats/test_format.py b/pandas/tests/io/formats/test_format.py
index f17b84b90638d..cbfa65e302730 100644
--- a/pandas/tests/io/formats/test_format.py
+++ b/pandas/tests/io/formats/test_format.py
@@ -1760,11 +1760,11 @@ def test_groups_repr_truncates(self):
 
         with option_context('display.max_rows', 2):
             x = df.groupby('a').groups
-            assert ', ... ,' in x.__repr__()
+            assert x.__repr__().endswith('...}')
 
         with option_context('display.max_rows', 5):
             x = df.groupby('a').groups
-            assert ', ... ,' not in x.__repr__()
+            assert not x.__repr__().endswith('...}')
 
 
 def gen_series_formatting():

From c74cbbaed8bc97cb07d0dfa81ba6d8cd1099e22c Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Sat, 30 Mar 2019 14:42:48 -0700
Subject: [PATCH 10/12] Accept isort formatting preference

---
 pandas/core/indexes/base.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index e6fa3e255f514..ca5f0d449d776 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -7,6 +7,7 @@
 import numpy as np
 
 from pandas._config.config import get_option
+
 from pandas._libs import (
     algos as libalgos, index as libindex, join as libjoin, lib)
 from pandas._libs.lib import is_datetime_array

From 9621669be1e6aa66587cc0871919aa558f01365d Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Wed, 10 Apr 2019 13:02:14 -0700
Subject: [PATCH 11/12] Add nonsense to AUTHORS.md

---
 AUTHORS.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/AUTHORS.md b/AUTHORS.md
index dcaaea101f4c8..4cdf79823bd73 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -55,3 +55,4 @@ license. Parts of NumPy, SciPy, numpydoc, bottleneck, which all have
 BSD-compatible licenses, are included. Their licenses follow the pandas
 license.
 
+asdf

From 38ecd1a7ce2da029a37b6bd39c01222228d49002 Mon Sep 17 00:00:00 2001
From: Ben <benarthur91@gmail.com>
Date: Wed, 10 Apr 2019 13:02:50 -0700
Subject: [PATCH 12/12] Revert "Add nonsense to AUTHORS.md"

This reverts commit 9621669be1e6aa66587cc0871919aa558f01365d.
---
 AUTHORS.md | 1 -
 1 file changed, 1 deletion(-)

diff --git a/AUTHORS.md b/AUTHORS.md
index 4cdf79823bd73..dcaaea101f4c8 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -55,4 +55,3 @@ license. Parts of NumPy, SciPy, numpydoc, bottleneck, which all have
 BSD-compatible licenses, are included. Their licenses follow the pandas
 license.
 
-asdf