REF: improve rendering of categories in CategoricalIndex (#45340)

Author: jbrockmendel

doc/source/whatsnew/v1.5.0.rst

@@ -30,7 +30,7 @@ enhancement2
 
 Other enhancements
 ^^^^^^^^^^^^^^^^^^
--
+- Improved the rendering of ``categories`` in :class:`CategoricalIndex` (:issue:`45218`)
 -
 
 .. ---------------------------------------------------------------------------

pandas/core/indexes/category.py

@@ -8,8 +8,6 @@
 
 import numpy as np
 
-from pandas._config import get_option
-
 from pandas._libs import index as libindex
 from pandas._typing import (
     Dtype,
@@ -347,16 +345,12 @@ def _format_attrs(self):
         """
         Return a list of tuples of the (attr,formatted_value)
         """
-        max_categories = (
-            10
-            if get_option("display.max_categories") == 0
-            else get_option("display.max_categories")
-        )
         attrs: list[tuple[str, str | int | bool | None]]
+
         attrs = [
             (
                 "categories",
-                ibase.default_pprint(self.categories, max_seq_items=max_categories),
+                "[" + ", ".join(self._data._repr_categories()) + "]",
             ),
             ("ordered", self.ordered),
         ]

pandas/tests/arrays/categorical/test_repr.py

@@ -382,7 +382,7 @@ def test_categorical_index_repr(self):
         assert repr(idx) == exp
 
         i = CategoricalIndex(Categorical(np.arange(10)))
-        exp = """CategoricalIndex([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], categories=[0, 1, 2, 3, 4, 5, 6, 7, ...], ordered=False, dtype='category')"""  # noqa:E501
+        exp = """CategoricalIndex([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], categories=[0, 1, 2, 3, ..., 6, 7, 8, 9], ordered=False, dtype='category')"""  # noqa:E501
         assert repr(i) == exp
 
     def test_categorical_index_repr_ordered(self):
@@ -391,7 +391,7 @@ def test_categorical_index_repr_ordered(self):
         assert repr(i) == exp
 
         i = CategoricalIndex(Categorical(np.arange(10), ordered=True))
-        exp = """CategoricalIndex([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], categories=[0, 1, 2, 3, 4, 5, 6, 7, ...], ordered=True, dtype='category')"""  # noqa:E501
+        exp = """CategoricalIndex([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], categories=[0, 1, 2, 3, ..., 6, 7, 8, 9], ordered=True, dtype='category')"""  # noqa:E501
         assert repr(i) == exp
 
     def test_categorical_index_repr_datetime(self):
@@ -498,7 +498,7 @@ def test_categorical_index_repr_period_ordered(self):
     def test_categorical_index_repr_timedelta(self):
         idx = timedelta_range("1 days", periods=5)
         i = CategoricalIndex(Categorical(idx))
-        exp = """CategoricalIndex(['1 days', '2 days', '3 days', '4 days', '5 days'], categories=[1 days 00:00:00, 2 days 00:00:00, 3 days 00:00:00, 4 days 00:00:00, 5 days 00:00:00], ordered=False, dtype='category')"""  # noqa:E501
+        exp = """CategoricalIndex(['1 days', '2 days', '3 days', '4 days', '5 days'], categories=[1 days, 2 days, 3 days, 4 days, 5 days], ordered=False, dtype='category')"""  # noqa:E501
         assert repr(i) == exp
 
         idx = timedelta_range("1 hours", periods=10)
@@ -507,14 +507,14 @@ def test_categorical_index_repr_timedelta(self):
                   '3 days 01:00:00', '4 days 01:00:00', '5 days 01:00:00',
                   '6 days 01:00:00', '7 days 01:00:00', '8 days 01:00:00',
                   '9 days 01:00:00'],
-                 categories=[0 days 01:00:00, 1 days 01:00:00, 2 days 01:00:00, 3 days 01:00:00, 4 days 01:00:00, 5 days 01:00:00, 6 days 01:00:00, 7 days 01:00:00, ...], ordered=False, dtype='category')"""  # noqa:E501
+                 categories=[0 days 01:00:00, 1 days 01:00:00, 2 days 01:00:00, 3 days 01:00:00, ..., 6 days 01:00:00, 7 days 01:00:00, 8 days 01:00:00, 9 days 01:00:00], ordered=False, dtype='category')"""  # noqa:E501
 
         assert repr(i) == exp
 
     def test_categorical_index_repr_timedelta_ordered(self):
         idx = timedelta_range("1 days", periods=5)
         i = CategoricalIndex(Categorical(idx, ordered=True))
-        exp = """CategoricalIndex(['1 days', '2 days', '3 days', '4 days', '5 days'], categories=[1 days 00:00:00, 2 days 00:00:00, 3 days 00:00:00, 4 days 00:00:00, 5 days 00:00:00], ordered=True, dtype='category')"""  # noqa:E501
+        exp = """CategoricalIndex(['1 days', '2 days', '3 days', '4 days', '5 days'], categories=[1 days, 2 days, 3 days, 4 days, 5 days], ordered=True, dtype='category')"""  # noqa:E501
         assert repr(i) == exp
 
         idx = timedelta_range("1 hours", periods=10)
@@ -523,7 +523,7 @@ def test_categorical_index_repr_timedelta_ordered(self):
                   '3 days 01:00:00', '4 days 01:00:00', '5 days 01:00:00',
                   '6 days 01:00:00', '7 days 01:00:00', '8 days 01:00:00',
                   '9 days 01:00:00'],
-                 categories=[0 days 01:00:00, 1 days 01:00:00, 2 days 01:00:00, 3 days 01:00:00, 4 days 01:00:00, 5 days 01:00:00, 6 days 01:00:00, 7 days 01:00:00, ...], ordered=True, dtype='category')"""  # noqa:E501
+                 categories=[0 days 01:00:00, 1 days 01:00:00, 2 days 01:00:00, 3 days 01:00:00, ..., 6 days 01:00:00, 7 days 01:00:00, 8 days 01:00:00, 9 days 01:00:00], ordered=True, dtype='category')"""  # noqa:E501
 
         assert repr(i) == exp
 

pandas/tests/indexes/categorical/test_formats.py

@@ -41,7 +41,7 @@ def test_string_categorical_index_repr(self):
         idx = CategoricalIndex(list("abcdefghijklmmo"))
         expected = """CategoricalIndex(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
                   'm', 'm', 'o'],
-                 categories=['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', ...], ordered=False, dtype='category')"""  # noqa:E501
+                 categories=['a', 'b', 'c', 'd', ..., 'k', 'l', 'm', 'o'], ordered=False, dtype='category')"""  # noqa:E501
 
         assert repr(idx) == expected
 
@@ -72,7 +72,7 @@ def test_string_categorical_index_repr(self):
         idx = CategoricalIndex(list("あいうえおかきくけこさしすせそ"))
         expected = """CategoricalIndex(['あ', 'い', 'う', 'え', 'お', 'か', 'き', 'く', 'け', 'こ', 'さ', 'し',
                   'す', 'せ', 'そ'],
-                 categories=['あ', 'い', 'う', 'え', 'お', 'か', 'き', 'く', ...], ordered=False, dtype='category')"""  # noqa:E501
+                 categories=['あ', 'い', 'う', 'え', ..., 'し', 'す', 'せ', 'そ'], ordered=False, dtype='category')"""  # noqa:E501
 
         assert repr(idx) == expected
 
@@ -109,6 +109,6 @@ def test_string_categorical_index_repr(self):
             idx = CategoricalIndex(list("あいうえおかきくけこさしすせそ"))
             expected = """CategoricalIndex(['あ', 'い', 'う', 'え', 'お', 'か', 'き', 'く', 'け', 'こ',
                   'さ', 'し', 'す', 'せ', 'そ'],
-                 categories=['あ', 'い', 'う', 'え', 'お', 'か', 'き', 'く', ...], ordered=False, dtype='category')"""  # noqa:E501
+                 categories=['あ', 'い', 'う', 'え', ..., 'し', 'す', 'せ', 'そ'], ordered=False, dtype='category')"""  # noqa:E501
 
             assert repr(idx) == expected