Make independent test cases for issue 18434

Author: Xbar

doc/source/whatsnew/v0.22.0.txt

@@ -140,6 +140,7 @@ Indexing
 - Bug in :func:`Series.truncate` which raises ``TypeError`` with a monotonic ``PeriodIndex`` (:issue:`17717`)
 - Bug in :func:`DataFrame.groupby` where tuples were interpreted as lists of keys rather than as keys (:issue:`17979`, :issue:`18249`)
 - Bug in :func:`MultiIndex.remove_unused_levels`` which would fill nan values (:issue:`18417`)
+- Bug in :func:`MultiIndex.from_tuples`` which would fail to take zipped tuples in python3 (:issue:`18434`)
 - Bug in :class:`IntervalIndex` where empty and purely NA data was constructed inconsistently depending on the construction method (:issue:`18421`)
 -
 

pandas/core/indexes/multi.py

@@ -1162,6 +1162,11 @@ def from_arrays(cls, arrays, sortorder=None, names=None):
  MultiIndex.from_product : Make a MultiIndex from cartesian product
  of iterables
  """
+ if not is_list_like(arrays):
+ raise TypeError("Input must be a list / sequence of array-likes.")
+ elif is_iterator(arrays):
+ arrays = list(arrays)
+
  # Check if lengths of all arrays are equal or not,
  # raise ValueError, if not
  for i in range(1, len(arrays)):
@@ -1206,6 +1211,11 @@ def from_tuples(cls, tuples, sortorder=None, names=None):
  MultiIndex.from_product : Make a MultiIndex from cartesian product
  of iterables
  """
+ if not is_list_like(tuples):
+ raise TypeError('Input must be a list / sequence of tuple-likes.')
+ elif is_iterator(tuples):
+ tuples = list(tuples)
+
  if len(tuples) == 0:
  if names is None:
  msg = 'Cannot infer number of levels from empty list'
@@ -1260,6 +1270,11 @@ def from_product(cls, iterables, sortorder=None, names=None):
  from pandas.core.categorical import _factorize_from_iterables
  from pandas.core.reshape.util import cartesian_product
 
+ if not is_list_like(iterables):
+ raise TypeError("Input must be a list / sequence of iterables.")
+ elif is_iterator(iterables):
+ iterables = list(iterables)
+
  labels, levels = _factorize_from_iterables(iterables)
  labels = cartesian_product(labels)
  return MultiIndex(levels, labels, sortorder=sortorder, names=names)

pandas/tests/indexes/test_multi.py

@@ -672,6 +672,7 @@ def test_from_arrays(self):
  for lev, lab in zip(self.index.levels, self.index.labels):
  arrays.append(np.asarray(lev).take(lab))
 
+ # list of arrays as input
  result = MultiIndex.from_arrays(arrays)
  assert list(result) == list(self.index)
 
@@ -681,6 +682,21 @@ def test_from_arrays(self):
  assert result.levels[0].equals(Index([Timestamp('20130101')]))
  assert result.levels[1].equals(Index(['a', 'b']))
 
+ def test_from_arrays_iterator(self):
+ # GH 18434
+ arrays = []
+ for lev, lab in zip(self.index.levels, self.index.labels):
+ arrays.append(np.asarray(lev).take(lab))
+
+ # iterator as input
+ result = MultiIndex.from_arrays(iter(arrays))
+ assert list(result) == list(self.index)
+
+ # invalid iterator input
+ with tm.assert_raises_regex(
+ TypeError, "Input must be a list / sequence of array-likes."):
+ MultiIndex.from_arrays(0)
+
  def test_from_arrays_index_series_datetimetz(self):
  idx1 = pd.date_range('2015-01-01 10:00', freq='D', periods=3,
  tz='US/Eastern')
@@ -827,6 +843,26 @@ def test_from_product(self):
  tm.assert_index_equal(result, expected)
  assert result.names == names
 
+ def test_from_product_iterator(self):
+ # GH 18434
+ first = ['foo', 'bar', 'buz']
+ second = ['a', 'b', 'c']
+ names = ['first', 'second']
+ tuples = [('foo', 'a'), ('foo', 'b'), ('foo', 'c'), ('bar', 'a'),
+ ('bar', 'b'), ('bar', 'c'), ('buz', 'a'), ('buz', 'b'),
+ ('buz', 'c')]
+ expected = MultiIndex.from_tuples(tuples, names=names)
+
+ # iterator as input
+ result = MultiIndex.from_product(iter([first, second]), names=names)
+ assert result.equals(expected)
+ assert result.names == names
+
+ # Invalid non-iterable input
+ with tm.assert_raises_regex(
+ TypeError, "Input must be a list / sequence of iterables."):
+ MultiIndex.from_product(0)
+
  def test_from_product_empty(self):
  # 0 levels
  with tm.assert_raises_regex(
@@ -1725,8 +1761,30 @@ def test_from_tuples(self):
  'from empty list',
  MultiIndex.from_tuples, [])
 
- idx = MultiIndex.from_tuples(((1, 2), (3, 4)), names=['a', 'b'])
- assert len(idx) == 2
+ expected = MultiIndex(levels=[[1, 3], [2, 4]],
+ labels=[[0, 1], [0, 1]],
+ names=['a', 'b'])
+
+ # input tuples
+ result = MultiIndex.from_tuples(((1, 2), (3, 4)), names=['a', 'b'])
+ assert expected.names == result.names
+ assert result.equals(expected)
+
+ def test_from_tuples_iterator(self):
+ # GH 18434
+ # input iterator for tuples
+ expected = MultiIndex(levels=[[1, 3], [2, 4]],
+ labels=[[0, 1], [0, 1]],
+ names=['a', 'b'])
+
+ result = MultiIndex.from_tuples(zip([1, 3], [2, 4]), names=['a', 'b'])
+ assert expected.names == result.names
+ assert result.equals(expected)
+
+ # input non-iterables
+ with tm.assert_raises_regex(
+ TypeError, 'Input must be a list / sequence of tuple-likes.'):
+ MultiIndex.from_tuples(0)
 
  def test_from_tuples_empty(self):
  # GH 16777