Improve docs

Author: topper-123

doc/source/whatsnew/v0.25.0.rst

@@ -19,6 +19,37 @@ These are the changes in pandas 0.25.0. See :ref:`release` for a full changelog
 including other versions of pandas.
 
 
+.. _whatsnew_0240.enhancements.multi_index_repr:
+
+Better repr for MultiIndex
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Printing of :class:`MultiIndex` instances now shows tuples of each row and ensures
+that the tuple items are vertically aligned, so it's now easier to understand
+the structure of the ``MultiIndex``. (:issue:`13480`):
+
+The repr now looks like this:
+
+.. ipython:: python
+
+   pd.MultiIndex.from_product([['a', 'abc'], range(500)])
+
+Previously, outputting a :class:`MultiIndex` printed all the ``levels`` and
+``labels`` of the ``MultiIndex``, which was visually unappealing and made
+the output more difficult to navigate:
+
+.. code-block:: ipython
+
+   >>>pd.MultiIndex.from_product([['a', 'abc'], range(5)])
+   MultiIndex(levels=[['a', 'abc'], [0, 1, 2, 3]],
+              labels=[[0, 0, 0, 0, 1, 1, 1, 1], [0, 1, 2, 3, 0, 1, 2, 3]])
+
+In the new repr, all values will be shown, if the number of rows is smaller
+than :attr:`options.display.max_seq_items` (default: 100 items). Horizontally,
+the output will truncate, if it's wider than :attr:`options.display.width`
+(default: 80 characters).
+
+
 .. _whatsnew_0250.enhancements.other:
 
 Other Enhancements

pandas/core/indexes/base.py

@@ -1308,17 +1308,24 @@ def set_names(self, names, level=None, inplace=False):
         >>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
         ...                                   [2018, 2019]])
         >>> idx
-        MultiIndex(levels=[['cobra', 'python'], [2018, 2019]],
-                   codes=[[1, 1, 0, 0], [0, 1, 0, 1]])
+        MultiIndex([('python', 2018),
+                    ('python', 2019),
+                    ( 'cobra', 2018),
+                    ( 'cobra', 2019)],
+                   dtype='object')
         >>> idx.set_names(['kind', 'year'], inplace=True)
         >>> idx
-        MultiIndex(levels=[['cobra', 'python'], [2018, 2019]],
-                   codes=[[1, 1, 0, 0], [0, 1, 0, 1]],
-                   names=['kind', 'year'])
+        MultiIndex([('python', 2018),
+                    ('python', 2019),
+                    ( 'cobra', 2018),
+                    ( 'cobra', 2019)],
+                   dtype='object', names=['kind', 'year'])
         >>> idx.set_names('species', level=0)
-        MultiIndex(levels=[['cobra', 'python'], [2018, 2019]],
-                   codes=[[1, 1, 0, 0], [0, 1, 0, 1]],
-                   names=['species', 'year'])
+        MultiIndex([('python', 2018),
+                    ('python', 2019),
+                    ( 'cobra', 2018),
+                    ( 'cobra', 2019)],
+                   dtype='object', names=['species', 'year'])
         """
 
         if level is not None and not isinstance(self, ABCMultiIndex):
@@ -1379,13 +1386,17 @@ def rename(self, name, inplace=False):
         ...                                   [2018, 2019]],
         ...                                   names=['kind', 'year'])
         >>> idx
-        MultiIndex(levels=[['cobra', 'python'], [2018, 2019]],
-                   codes=[[1, 1, 0, 0], [0, 1, 0, 1]],
-                   names=['kind', 'year'])
+        MultiIndex([('python', 2018),
+                    ('python', 2019),
+                    ( 'cobra', 2018),
+                    ( 'cobra', 2019)],
+                   dtype='object', names=['kind', 'year'])
         >>> idx.rename(['species', 'year'])
-        MultiIndex(levels=[['cobra', 'python'], [2018, 2019]],
-                   codes=[[1, 1, 0, 0], [0, 1, 0, 1]],
-                   names=['species', 'year'])
+        MultiIndex([('python', 2018),
+                    ('python', 2019),
+                    ( 'cobra', 2018),
+                    ( 'cobra', 2019)],
+                   dtype='object', names=['species', 'year'])
         >>> idx.rename('species')
         Traceback (most recent call last):
         TypeError: Must pass list-like as `names`.
@@ -5313,9 +5324,9 @@ def ensure_index_from_sequences(sequences, names=None):
 
     >>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
                                     names=['L1', 'L2'])
-    MultiIndex(levels=[['a'], ['a', 'b']],
-               codes=[[0, 0], [0, 1]],
-               names=['L1', 'L2'])
+    MultiIndex([('a', 'a'),
+                ('a', 'b')],
+               dtype='object', names=['L1', 'L2'])
 
     See Also
     --------
@@ -5354,8 +5365,14 @@ def ensure_index(index_like, copy=False):
     Index([('a', 'a'), ('b', 'c')], dtype='object')
 
     >>> ensure_index([['a', 'a'], ['b', 'c']])
+<<<<<<< HEAD
     MultiIndex(levels=[['a'], ['b', 'c']],
                codes=[[0, 0], [0, 1]])
+=======
+    MultiIndex([('a', 'b'),
+                ('a', 'c')],
+               dtype='object')
+>>>>>>> Improve docs
 
     See Also
     --------

pandas/core/indexes/multi.py

@@ -32,8 +32,7 @@
 from pandas.core.indexes.frozen import FrozenList, _ensure_frozen
 import pandas.core.missing as missing
 
-from pandas.io.formats.printing import (
-    default_pprint, format_object_summary, pprint_thing)
+from pandas.io.formats.printing import format_object_summary, pprint_thing
 
 _index_doc_kwargs = dict(ibase._index_doc_kwargs)
 _index_doc_kwargs.update(

pandas/core/strings.py

@@ -2481,8 +2481,9 @@ def rsplit(self, pat=None, n=-1, expand=False):
     Which will create a MultiIndex:
 
     >>> idx.str.partition()
-    MultiIndex(levels=[['X', 'Y'], [' '], ['123', '999']],
-               codes=[[0, 1], [0, 0], [0, 1]])
+    MultiIndex([('X', ' ', '123'),
+                ('Y', ' ', '999')],
+               dtype='object')
 
     Or an index with tuples with ``expand=False``: