Merge pull request #4935 from jtratner/multiindex-smart-repr

ENH: Better string representation for MultiIndex

Author: jtratner

doc/source/release.rst

@@ -131,6 +131,8 @@ Improvements to existing features
  (:issue:`3441`, :issue:`4933`)
  - ``pandas`` is now tested with two different versions of ``statsmodels``
  (0.4.3 and 0.5.0) (:issue:`4981`).
+ - Better string representations of ``MultiIndex`` (including ability to roundtrip
+ via ``repr``). (:issue:`3347`, :issue:`4935`)
 
 API Changes
 ~~~~~~~~~~~

pandas/core/index.py

@@ -1,6 +1,6 @@
 # pylint: disable=E1101,E1103,W0232
 from functools import partial
-from pandas.compat import range, zip, lrange, lzip
+from pandas.compat import range, zip, lrange, lzip, u
 from pandas import compat
 import numpy as np
 
@@ -17,6 +17,10 @@
 from pandas.core.common import _values_from_object, is_float, is_integer
 from pandas.core.config import get_option
 
+# simplify
+default_pprint = lambda x: com.pprint_thing(x, escape_chars=('\t', '\r', '\n'),
+ quote_strings=True)
+
 
 __all__ = ['Index']
 
@@ -2052,18 +2056,40 @@ def _array_values(self):
  def dtype(self):
  return np.dtype('O')
 
+ def __repr__(self):
+ encoding = get_option('display.encoding')
+ attrs = [('levels', default_pprint(self.levels)),
+ ('labels', default_pprint(self.labels))]
+ if not all(name is None for name in self.names):
+ attrs.append(('names', default_pprint(self.names)))
+ if self.sortorder is not None:
+ attrs.append(('sortorder', default_pprint(self.sortorder)))
+
+ space = ' ' * (len(self.__class__.__name__) + 1)
+ prepr = (u("\n%s") % space).join([u("%s=%s") % (k, v)
+ for k, v in attrs])
+ res = u("%s(%s)") % (self.__class__.__name__, prepr)
+
+ if not compat.PY3:
+ # needs to be str in Python 2
+ res = res.encode(encoding)
+ return res
+
+
  def __unicode__(self):
  """
  Return a string representation for a particular Index
 
  Invoked by unicode(df) in py2 only. Yields a Unicode String in both py2/py3.
  """
- output = 'MultiIndex\n%s'
-
- summary = com.pprint_thing(self, escape_chars=('\t', '\r', '\n'),
- quote_strings=True)
-
- return output % summary
+ rows = self.format(names=True)
+ max_rows = get_option('display.max_rows')
+ if len(rows) > max_rows:
+ spaces = (len(rows[0]) - 3) // 2
+ centered = ' ' * spaces
+ half = max_rows // 2
+ rows = rows[:half] + [centered + '...' + centered] + rows[-half:]
+ return "\n".join(rows)
 
  def __len__(self):
  return len(self.labels[0])