Review

pandas/core/reshape/merge.py

@@ -1164,11 +1164,8 @@ def _convert_to_mulitindex(index):
  if isinstance(index, MultiIndex):
  return index
  else:
- levels = [index.values]
- labels = [list(range(index.size))]
- names = [index.name]
- return MultiIndex(levels=levels, labels=labels, names=names,
- verify_integrity=False)
+ return MultiIndex.from_arrays([index.values],
+ names=[index.name])
 
  # For multi-multi joins with one overlapping level,
  # the returned index if of type Index

pandas/tests/reshape/merge/test_multi.py

@@ -40,6 +40,44 @@ def right():
  columns=['j_one', 'j_two', 'j_three'])
 
 
+@pytest.fixture
+def left_multi():
+ return (
+ DataFrame(
+ dict(Origin=['A', 'A', 'B', 'B', 'C'],
+ Destination=['A', 'B', 'A', 'C', 'A'],
+ Period=['AM', 'AM', 'IP', 'AM', 'OP'],
+ TripPurp=['hbw', 'nhb', 'hbo', 'nhb', 'hbw'],
+ Trips=[1987, 3647, 2470, 4296, 4444]),
+ columns=['Origin', 'Destination', 'Period',
+ 'TripPurp', 'Trips'])
+ .set_index(['Origin', 'Destination', 'Period', 'TripPurp']))
+
+
+@pytest.fixture
+def right_multi():
+ return (
+ DataFrame(
+ dict(Origin=['A', 'A', 'B', 'B', 'C', 'C', 'E'],
+ Destination=['A', 'B', 'A', 'B', 'A', 'B', 'F'],
+ Period=['AM', 'AM', 'IP', 'AM', 'OP', 'IP', 'AM'],
+ LinkType=['a', 'b', 'c', 'b', 'a', 'b', 'a'],
+ Distance=[100, 80, 90, 80, 75, 35, 55]),
+ columns=['Origin', 'Destination', 'Period',
+ 'LinkType', 'Distance'])
+ .set_index(['Origin', 'Destination', 'Period', 'LinkType']))
+
+
+@pytest.fixture
+def on_cols_multi():
+ return ['Origin', 'Destination', 'Period']
+
+
+@pytest.fixture
+def idx_cols_multi():
+ return ['Origin', 'Destination', 'Period', 'TripPurp', 'LinkType']
+
+
 class TestMergeMulti(object):
 
  def setup_method(self):
@@ -549,66 +587,28 @@ def test_join_multi_levels2(self):
  tm.assert_frame_equal(result, expected)
 
 
-@pytest.fixture
-def left_multi():
- return (
- DataFrame(
- dict(Origin=['A', 'A', 'B', 'B', 'C'],
- Destination=['A', 'B', 'A', 'C', 'A'],
- Period=['AM', 'AM', 'IP', 'AM', 'OP'],
- TripPurp=['hbw', 'nhb', 'hbo', 'nhb', 'hbw'],
- Trips=[1987, 3647, 2470, 4296, 4444]),
- columns=['Origin', 'Destination', 'Period',
- 'TripPurp', 'Trips'])
- .set_index(['Origin', 'Destination', 'Period', 'TripPurp']))
-
-
-@pytest.fixture
-def right_multi():
- return (
- DataFrame(
- dict(Origin=['A', 'A', 'B', 'B', 'C', 'C', 'E'],
- Destination=['A', 'B', 'A', 'B', 'A', 'B', 'F'],
- Period=['AM', 'AM', 'IP', 'AM', 'OP', 'IP', 'AM'],
- LinkType=['a', 'b', 'c', 'b', 'a', 'b', 'a'],
- Distance=[100, 80, 90, 80, 75, 35, 55]),
- columns=['Origin', 'Destination', 'Period',
- 'LinkType', 'Distance'])
- .set_index(['Origin', 'Destination', 'Period', 'LinkType']))
-
-
-@pytest.fixture
-def on_cols():
- return ['Origin', 'Destination', 'Period']
-
-
-@pytest.fixture
-def idx_cols():
- return ['Origin', 'Destination', 'Period', 'TripPurp', 'LinkType']
-
-
 class TestJoinMultiMulti(object):
 
  def test_join_multi_multi(self, left_multi, right_multi, join_type,
- on_cols, idx_cols):
+ on_cols_multi, idx_cols_multi):
  # Multi-index join tests
  expected = (pd.merge(left_multi.reset_index(),
  right_multi.reset_index(),
- how=join_type, on=on_cols).set_index(idx_cols)
+ how=join_type, on=on_cols_multi).set_index(idx_cols_multi)
  .sort_index())
 
  result = left_multi.join(right_multi, how=join_type).sort_index()
  tm.assert_frame_equal(result, expected)
 
  def test_join_multi_empty_frames(self, left_multi, right_multi, join_type,
- on_cols, idx_cols):
+ on_cols_multi, idx_cols_multi):
 
  left_multi = left_multi.drop(columns=left_multi.columns)
  right_multi = right_multi.drop(columns=right_multi.columns)
 
  expected = (pd.merge(left_multi.reset_index(),
  right_multi.reset_index(),
- how=join_type, on=on_cols).set_index(idx_cols)
+ how=join_type, on=on_cols_multi).set_index(idx_cols_multi)
  .sort_index())
 
  result = left_multi.join(right_multi, how=join_type).sort_index()