BUG: Bug in Index construction with a mixed list of tuples #10697)

Author: jreback

doc/source/whatsnew/v0.17.0.txt

@@ -367,7 +367,7 @@ Bug Fixes
 - Bug in ``Index.drop_duplicates`` dropping name(s) (:issue:`10115`)
 - Bug in ``pd.Series`` when setting a value on an empty ``Series`` whose index has a frequency. (:issue:`10193`)
 - Bug in ``DataFrame.plot`` raises ``ValueError`` when color name is specified by multiple characters (:issue:`10387`)
-
+- Bug in ``Index`` construction with a mixed list of tuples (:issue:`10697`)
 - Bug in ``DataFrame.reset_index`` when index contains `NaT`. (:issue:`10388`)
 - Bug in ``ExcelReader`` when worksheet is empty (:issue:`6403`)
 - Bug in ``Table.select_column`` where name is not preserved (:issue:`10392`)

pandas/core/index.py

@@ -164,16 +164,21 @@ def __new__(cls, data=None, dtype=None, copy=False, name=None, fastpath=False,
  cls._scalar_data_error(data)
  else:
  if tupleize_cols and isinstance(data, list) and data and isinstance(data[0], tuple):
- try:
 
- # must be orderable in py3
- if compat.PY3:
- sorted(data)
- return MultiIndex.from_tuples(
- data, names=name or kwargs.get('names'))
- except (TypeError, KeyError):
- # python2 - MultiIndex fails on mixed types
- pass
+ # we must be all tuples, otherwise don't construct
+ # 10697
+ if all( isinstance(e, tuple) for e in data ):
+
+ try:
+
+ # must be orderable in py3
+ if compat.PY3:
+ sorted(data)
+ return MultiIndex.from_tuples(
+ data, names=name or kwargs.get('names'))
+ except (TypeError, KeyError):
+ # python2 - MultiIndex fails on mixed types
+ pass
 
  # other iterable of some kind
  subarr = com._asarray_tuplesafe(data, dtype=object)

pandas/tests/test_index.py

@@ -553,6 +553,15 @@ def test_constructor_corner(self):
  # corner case
  self.assertRaises(TypeError, Index, 0)
 
+ def test_consruction_list_mixed_tuples(self):
+ # 10697
+ # if we are constructing from a mixed list of tuples, make sure that we
+ # are independent of the sorting order
+ idx1 = Index([('A',1),'B'])
+ self.assertIsInstance(idx1, Index) and self.assertNotInstance(idx1, MultiIndex)
+ idx2 = Index(['B',('A',1)])
+ self.assertIsInstance(idx2, Index) and self.assertNotInstance(idx2, MultiIndex)
+
  def test_constructor_from_series(self):
 
  expected = DatetimeIndex([Timestamp('20110101'),Timestamp('20120101'),Timestamp('20130101')])

pandas/tools/tests/test_merge.py

@@ -2002,6 +2002,13 @@ def test_dups_index(self):
  result = df.append(df)
  assert_frame_equal(result, expected)
 
+ def test_with_mixed_tuples(self):
+ # 10697
+ # columns have mixed tuples, so handle properly
+ df1 = DataFrame({ u'A' : 'foo', (u'B',1) : 'bar' },index=range(2))
+ df2 = DataFrame({ u'B' : 'foo', (u'B',1) : 'bar' },index=range(2))
+ result = concat([df1,df2])
+
  def test_join_dups(self):
 
  # joining dups