add more tests

pandas/core/indexes/interval.py

@@ -1029,7 +1029,7 @@ def equals(self, other):
                 self.closed == other.closed)
 
     def _setop(op_name):
-        def func(self, other):
+        def func(self, other, sort=True):
             other = self._as_like_interval_index(other)
 
             # GH 19016: ensure set op will not return a prohibited dtype
@@ -1040,7 +1040,11 @@ def func(self, other):
                        'objects that have compatible dtypes')
                 raise TypeError(msg.format(op=op_name))
 
-            result = getattr(self._multiindex, op_name)(other._multiindex)
+            if op_name == 'difference':
+                result = getattr(self._multiindex, op_name)(other._multiindex,
+                                                            sort)
+            else:
+                result = getattr(self._multiindex, op_name)(other._multiindex)
             result_name = self.name if self.name == other.name else None
 
             # GH 19101: ensure empty results have correct dtype

pandas/core/indexes/multi.py

@@ -2791,8 +2791,14 @@ def difference(self, other, sort=True):
                               labels=[[]] * self.nlevels,
                               names=result_names, verify_integrity=False)
 
-        difference = set(self._ndarray_values) - set(other._ndarray_values)
+        this = self._get_unique_index()
 
+        indexer = this.get_indexer(other)
+        indexer = indexer.take((indexer != -1).nonzero()[0])
+
+        label_diff = np.setdiff1d(np.arange(this.size), indexer,
+                                  assume_unique=True)
+        difference = this.values.take(label_diff)
         if sort:
             difference = sorted(difference)
 

pandas/tests/indexes/common.py

@@ -668,12 +668,13 @@ def test_union_base(self):
                 with tm.assert_raises_regex(TypeError, msg):
                     result = first.union([1, 2, 3])
 
-    def test_difference_base(self):
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference_base(self, sort):
         for name, idx in compat.iteritems(self.indices):
             first = idx[2:]
             second = idx[:4]
             answer = idx[4:]
-            result = first.difference(second)
+            result = first.difference(second, sort)
 
             if isinstance(idx, CategoricalIndex):
                 pass
@@ -687,21 +688,21 @@ def test_difference_base(self):
                 if isinstance(idx, PeriodIndex):
                     msg = "can only call with other PeriodIndex-ed objects"
                     with tm.assert_raises_regex(ValueError, msg):
-                        result = first.difference(case)
+                        result = first.difference(case, sort)
                 elif isinstance(idx, CategoricalIndex):
                     pass
                 elif isinstance(idx, (DatetimeIndex, TimedeltaIndex)):
                     assert result.__class__ == answer.__class__
                     tm.assert_numpy_array_equal(result.sort_values().asi8,
                                                 answer.sort_values().asi8)
                 else:
-                    result = first.difference(case)
+                    result = first.difference(case, sort)
                     assert tm.equalContents(result, answer)
 
             if isinstance(idx, MultiIndex):
                 msg = "other must be a MultiIndex or a list of tuples"
                 with tm.assert_raises_regex(TypeError, msg):
-                    result = first.difference([1, 2, 3])
+                    result = first.difference([1, 2, 3], sort)
 
     def test_symmetric_difference(self):
         for name, idx in compat.iteritems(self.indices):

pandas/tests/indexes/datetimes/test_setops.py

@@ -206,47 +206,55 @@ def test_intersection_bug_1708(self):
         assert len(result) == 0
 
     @pytest.mark.parametrize("tz", tz)
-    def test_difference(self, tz):
-        rng1 = pd.date_range('1/1/2000', freq='D', periods=5, tz=tz)
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference(self, tz, sort):
+        rng_dates = ['1/2/2000', '1/3/2000', '1/1/2000', '1/4/2000',
+                     '1/5/2000']
+
+        rng1 = pd.DatetimeIndex(rng_dates, tz=tz)
         other1 = pd.date_range('1/6/2000', freq='D', periods=5, tz=tz)
-        expected1 = pd.date_range('1/1/2000', freq='D', periods=5, tz=tz)
+        expected1 = pd.DatetimeIndex(rng_dates, tz=tz)
 
-        rng2 = pd.date_range('1/1/2000', freq='D', periods=5, tz=tz)
+        rng2 = pd.DatetimeIndex(rng_dates, tz=tz)
         other2 = pd.date_range('1/4/2000', freq='D', periods=5, tz=tz)
-        expected2 = pd.date_range('1/1/2000', freq='D', periods=3, tz=tz)
+        expected2 = pd.DatetimeIndex(rng_dates[:3], tz=tz)
 
-        rng3 = pd.date_range('1/1/2000', freq='D', periods=5, tz=tz)
+        rng3 = pd.DatetimeIndex(rng_dates, tz=tz)
         other3 = pd.DatetimeIndex([], tz=tz)
-        expected3 = pd.date_range('1/1/2000', freq='D', periods=5, tz=tz)
+        expected3 = pd.DatetimeIndex(rng_dates, tz=tz)
 
         for rng, other, expected in [(rng1, other1, expected1),
                                      (rng2, other2, expected2),
                                      (rng3, other3, expected3)]:
-            result_diff = rng.difference(other)
+            result_diff = rng.difference(other, sort)
+            if sort:
+                expected = expected.sort_values()
             tm.assert_index_equal(result_diff, expected)
 
-    def test_difference_freq(self):
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference_freq(self, sort):
         # GH14323: difference of DatetimeIndex should not preserve frequency
 
         index = date_range("20160920", "20160925", freq="D")
         other = date_range("20160921", "20160924", freq="D")
         expected = DatetimeIndex(["20160920", "20160925"], freq=None)
-        idx_diff = index.difference(other)
+        idx_diff = index.difference(other, sort)
         tm.assert_index_equal(idx_diff, expected)
         tm.assert_attr_equal('freq', idx_diff, expected)
 
         other = date_range("20160922", "20160925", freq="D")
-        idx_diff = index.difference(other)
+        idx_diff = index.difference(other, sort)
         expected = DatetimeIndex(["20160920", "20160921"], freq=None)
         tm.assert_index_equal(idx_diff, expected)
         tm.assert_attr_equal('freq', idx_diff, expected)
 
-    def test_datetimeindex_diff(self):
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_datetimeindex_diff(self, sort):
         dti1 = DatetimeIndex(freq='Q-JAN', start=datetime(1997, 12, 31),
                              periods=100)
         dti2 = DatetimeIndex(freq='Q-JAN', start=datetime(1997, 12, 31),
                              periods=98)
-        assert len(dti1.difference(dti2)) == 2
+        assert len(dti1.difference(dti2, sort)) == 2
 
     def test_datetimeindex_union_join_empty(self):
         dti = DatetimeIndex(start='1/1/2001', end='2/1/2001', freq='D')

pandas/tests/indexes/interval/test_interval.py

@@ -798,19 +798,26 @@ def test_intersection(self, closed):
         result = index.intersection(other)
         tm.assert_index_equal(result, expected)
 
-    def test_difference(self, closed):
-        index = self.create_index(closed=closed)
-        tm.assert_index_equal(index.difference(index[:1]), index[1:])
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference(self, closed, sort):
+        index = IntervalIndex.from_arrays([1, 0, 3, 2],
+                                          [1, 2, 3, 4],
+                                          closed=closed)
+        result = index.difference(index[:1], sort)
+        expected = index[1:]
+        if sort:
+            expected = expected.sort_values()
+        tm.assert_index_equal(result, expected)
 
         # GH 19101: empty result, same dtype
-        result = index.difference(index)
+        result = index.difference(index, sort)
         expected = IntervalIndex(np.array([], dtype='int64'), closed=closed)
         tm.assert_index_equal(result, expected)
 
         # GH 19101: empty result, different dtypes
         other = IntervalIndex.from_arrays(index.left.astype('float64'),
                                           index.right, closed=closed)
-        result = index.difference(other)
+        result = index.difference(other, sort)
         tm.assert_index_equal(result, expected)
 
     def test_symmetric_difference(self, closed):

pandas/tests/indexes/multi/test_set_ops.py

@@ -4,6 +4,7 @@
 import pandas as pd
 import pandas.util.testing as tm
 from pandas import MultiIndex, Series
+import pytest
 
 
 def test_setops_errorcases(idx):
@@ -58,24 +59,25 @@ def test_union_base(idx):
         result = first.union([1, 2, 3])
 
 
-def test_difference_base(idx):
+@pytest.mark.parametrize("sort", [True, False])
+def test_difference_base(idx, sort):
     first = idx[2:]
     second = idx[:4]
     answer = idx[4:]
-    result = first.difference(second)
+    result = first.difference(second, sort)
 
     assert tm.equalContents(result, answer)
 
     # GH 10149
     cases = [klass(second.values)
              for klass in [np.array, Series, list]]
     for case in cases:
-        result = first.difference(case)
+        result = first.difference(case, sort)
         assert tm.equalContents(result, answer)
 
     msg = "other must be a MultiIndex or a list of tuples"
     with tm.assert_raises_regex(TypeError, msg):
-        result = first.difference([1, 2, 3])
+        result = first.difference([1, 2, 3], sort)
 
 
 def test_symmetric_difference(idx):
@@ -103,11 +105,17 @@ def test_empty(idx):
     assert idx[:0].empty
 
 
-def test_difference(idx):
+@pytest.mark.parametrize("sort", [True, False])
+def test_difference(idx, sort):
 
     first = idx
-    result = first.difference(idx[-3:])
-    expected = MultiIndex.from_tuples(sorted(idx[:-3].values),
+    result = first.difference(idx[-3:], sort)
+    vals = idx[:-3].values
+
+    if sort:
+        vals = sorted(vals)
+
+    expected = MultiIndex.from_tuples(vals,
                                       sortorder=0,
                                       names=idx.names)
 
@@ -116,44 +124,44 @@ def test_difference(idx):
     assert result.names == idx.names
 
     # empty difference: reflexive
-    result = idx.difference(idx)
+    result = idx.difference(idx, sort)
     expected = idx[:0]
     assert result.equals(expected)
     assert result.names == idx.names
 
     # empty difference: superset
-    result = idx[-3:].difference(idx)
+    result = idx[-3:].difference(idx, sort)
     expected = idx[:0]
     assert result.equals(expected)
     assert result.names == idx.names
 
     # empty difference: degenerate
-    result = idx[:0].difference(idx)
+    result = idx[:0].difference(idx, sort)
     expected = idx[:0]
     assert result.equals(expected)
     assert result.names == idx.names
 
     # names not the same
     chunklet = idx[-3:]
     chunklet.names = ['foo', 'baz']
-    result = first.difference(chunklet)
+    result = first.difference(chunklet, sort)
     assert result.names == (None, None)
 
     # empty, but non-equal
-    result = idx.difference(idx.sortlevel(1)[0])
+    result = idx.difference(idx.sortlevel(1)[0], sort)
     assert len(result) == 0
 
     # raise Exception called with non-MultiIndex
-    result = first.difference(first.values)
+    result = first.difference(first.values, sort)
     assert result.equals(first[:0])
 
     # name from empty array
-    result = first.difference([])
+    result = first.difference([], sort)
     assert first.equals(result)
     assert first.names == result.names
 
     # name from non-empty array
-    result = first.difference([('foo', 'one')])
+    result = first.difference([('foo', 'one')], sort)
     expected = pd.MultiIndex.from_tuples([('bar', 'one'), ('baz', 'two'), (
         'foo', 'two'), ('qux', 'one'), ('qux', 'two')])
     expected.names = first.names

pandas/tests/indexes/period/test_period.py

@@ -72,20 +72,21 @@ def test_no_millisecond_field(self):
         with pytest.raises(AttributeError):
             DatetimeIndex([]).millisecond
 
-    def test_difference_freq(self):
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference_freq(self, sort):
         # GH14323: difference of Period MUST preserve frequency
         # but the ability to union results must be preserved
 
         index = period_range("20160920", "20160925", freq="D")
 
         other = period_range("20160921", "20160924", freq="D")
         expected = PeriodIndex(["20160920", "20160925"], freq='D')
-        idx_diff = index.difference(other)
+        idx_diff = index.difference(other, sort)
         tm.assert_index_equal(idx_diff, expected)
         tm.assert_attr_equal('freq', idx_diff, expected)
 
         other = period_range("20160922", "20160925", freq="D")
-        idx_diff = index.difference(other)
+        idx_diff = index.difference(other, sort)
         expected = PeriodIndex(["20160920", "20160921"], freq='D')
         tm.assert_index_equal(idx_diff, expected)
         tm.assert_attr_equal('freq', idx_diff, expected)

pandas/tests/indexes/period/test_setops.py

@@ -204,37 +204,49 @@ def test_intersection_cases(self):
         result = rng.intersection(rng[0:0])
         assert len(result) == 0
 
-    def test_difference(self):
+    @pytest.mark.parametrize("sort", [True, False])
+    def test_difference(self, sort):
         # diff
-        rng1 = pd.period_range('1/1/2000', freq='D', periods=5)
+        period_rng = ['1/3/2000', '1/2/2000', '1/1/2000', '1/5/2000',
+                      '1/4/2000']
+        rng1 = pd.PeriodIndex(period_rng, freq='D')
         other1 = pd.period_range('1/6/2000', freq='D', periods=5)
-        expected1 = pd.period_range('1/1/2000', freq='D', periods=5)
+        expected1 = rng1
 
-        rng2 = pd.period_range('1/1/2000', freq='D', periods=5)
+        rng2 = pd.PeriodIndex(period_rng, freq='D')
         other2 = pd.period_range('1/4/2000', freq='D', periods=5)
-        expected2 = pd.period_range('1/1/2000', freq='D', periods=3)
+        expected2 = pd.PeriodIndex(['1/3/2000', '1/2/2000', '1/1/2000'],
+                                   freq='D')
 
-        rng3 = pd.period_range('1/1/2000', freq='D', periods=5)
+        rng3 = pd.PeriodIndex(period_rng, freq='D')
         other3 = pd.PeriodIndex([], freq='D')
-        expected3 = pd.period_range('1/1/2000', freq='D', periods=5)
+        expected3 = rng3
 
-        rng4 = pd.period_range('2000-01-01 09:00', freq='H', periods=5)
+        period_rng = ['2000-01-01 10:00', '2000-01-01 09:00',
+                      '2000-01-01 12:00', '2000-01-01 11:00',
+                      '2000-01-01 13:00']
+        rng4 = pd.PeriodIndex(period_rng, freq='H')
         other4 = pd.period_range('2000-01-02 09:00', freq='H', periods=5)
         expected4 = rng4
 
-        rng5 = pd.PeriodIndex(['2000-01-01 09:01', '2000-01-01 09:03',
+        rng5 = pd.PeriodIndex(['2000-01-01 09:03', '2000-01-01 09:01',
                                '2000-01-01 09:05'], freq='T')
         other5 = pd.PeriodIndex(
             ['2000-01-01 09:01', '2000-01-01 09:05'], freq='T')
         expected5 = pd.PeriodIndex(['2000-01-01 09:03'], freq='T')
 
-        rng6 = pd.period_range('2000-01-01', freq='M', periods=7)
+        period_rng = ['2000-02-01', '2000-01-01', '2000-06-01',
+                      '2000-07-01', '2000-05-01', '2000-03-01',
+                      '2000-04-01']
+        rng6 = pd.PeriodIndex(period_rng, freq='M')
         other6 = pd.period_range('2000-04-01', freq='M', periods=7)
-        expected6 = pd.period_range('2000-01-01', freq='M', periods=3)
+        expected6 = pd.PeriodIndex(['2000-02-01', '2000-01-01', '2000-03-01'],
+                                   freq='M')
 
-        rng7 = pd.period_range('2003-01-01', freq='A', periods=5)
+        period_rng = ['2003', '2007', '2006', '2005', '2004']
+        rng7 = pd.PeriodIndex(period_rng, freq='A')
         other7 = pd.period_range('1998-01-01', freq='A', periods=8)
-        expected7 = pd.period_range('2006-01-01', freq='A', periods=2)
+        expected7 = pd.PeriodIndex(['2007', '2006'], freq='A')
 
         for rng, other, expected in [(rng1, other1, expected1),
                                      (rng2, other2, expected2),
@@ -243,5 +255,7 @@ def test_difference(self):
                                      (rng5, other5, expected5),
                                      (rng6, other6, expected6),
                                      (rng7, other7, expected7), ]:
-            result_union = rng.difference(other)
+            result_union = rng.difference(other, sort)
+            if sort:
+                expected = expected.sort_values()
             tm.assert_index_equal(result_union, expected)