Generalize NA Compat

doc/source/whatsnew/v0.21.1.txt

@@ -62,7 +62,6 @@ Bug Fixes
 - Bug in ``pd.Series.rolling.skew()`` and ``rolling.kurt()`` with all equal values has floating issue (:issue:`18044`)
 - Bug in ``pd.DataFrameGroupBy.count()`` when counting over a datetimelike column (:issue:`13393`)
 - Bug in ``pd.concat`` when empty and non-empty DataFrames or Series are concatenated (:issue:`18178` :issue:`18187`)
-- Bug in ``IntervalIndex.insert`` when attempting to insert ``NaN`` (:issue:`18295`)
 
 Conversion
 ^^^^^^^^^^

doc/source/whatsnew/v0.22.0.txt

@@ -47,7 +47,7 @@ Other API Changes
 - :class:`CacheableOffset` and :class:`WeekDay` are no longer available in the ``pandas.tseries.offsets`` module (:issue:`17830`)
 - `tseries.frequencies.get_freq_group()` and `tseries.frequencies.DAYS` are removed from the public API (:issue:`18034`)
 - :func:`Series.truncate` and :func:`DataFrame.truncate` will raise a ``ValueError`` if the index is not sorted instead of an unhelpful ``KeyError`` (:issue:`17935`)
-
+- Inserting missing values into indexes will work for all types of indexes and automatically insert the correct type of missing value (``NaN``, ``NaT``, etc.) regardless of the type passed in (:issue:`18295`)
 
 .. _whatsnew_0220.deprecations:
 

pandas/core/indexes/base.py

@@ -3728,6 +3728,10 @@ def insert(self, loc, item):
         -------
         new_index : Index
         """
+        if lib.checknull(item):
+            # GH 18295
+            item = self._na_value
+
         _self = np.asarray(self)
         item = self._coerce_scalar_to_index(item)._values
         idx = np.concatenate((_self[:loc], item, _self[loc:]))

pandas/core/indexes/category.py

@@ -1,5 +1,5 @@
 import numpy as np
-from pandas._libs import index as libindex
+from pandas._libs import index as libindex, lib
 
 from pandas import compat
 from pandas.compat.numpy import function as nv
@@ -688,7 +688,7 @@ def insert(self, loc, item):
 
         """
         code = self.categories.get_indexer([item])
-        if (code == -1):
+        if (code == -1) and not lib.checknull(item):
             raise TypeError("cannot insert an item into a CategoricalIndex "
                             "that is not already an existing category")
 

pandas/core/indexes/datetimes.py

@@ -1751,6 +1751,9 @@ def insert(self, loc, item):
         -------
         new_index : Index
         """
+        if lib.checknull(item):
+            # GH 18295
+            item = self._na_value
 
         freq = None
 
@@ -1767,14 +1770,14 @@ def insert(self, loc, item):
                 elif (loc == len(self)) and item - self.freq == self[-1]:
                     freq = self.freq
             item = _to_m8(item, tz=self.tz)
+
         try:
             new_dates = np.concatenate((self[:loc].asi8, [item.view(np.int64)],
                                         self[loc:].asi8))
             if self.tz is not None:
                 new_dates = conversion.tz_convert(new_dates, 'UTC', self.tz)
             return DatetimeIndex(new_dates, name=self.name, freq=freq,
                                  tz=self.tz)
-
         except (AttributeError, TypeError):
 
             # fall back to object index

pandas/core/indexes/interval.py

@@ -22,7 +22,7 @@
     Index, _ensure_index,
     default_pprint, _index_shared_docs)
 
-from pandas._libs import Timestamp, Timedelta
+from pandas._libs import lib, Timestamp, Timedelta
 from pandas._libs.interval import (
     Interval, IntervalMixin, IntervalTree,
     intervals_to_interval_bounds)
@@ -985,12 +985,8 @@ def insert(self, loc, item):
                                  'side as the index')
             left_insert = item.left
             right_insert = item.right
-        elif is_scalar(item) and isna(item):
+        elif lib.checknull(item):
             # GH 18295
-            if item is not self.left._na_value:
-                raise TypeError('cannot insert with incompatible NA value: '
-                                'got {item}, expected {na}'
-                                .format(item=item, na=self.left._na_value))
             left_insert = right_insert = item
         else:
             raise ValueError('can only insert Interval objects and NA into '

pandas/core/indexes/timedeltas.py

@@ -849,16 +849,18 @@ def insert(self, loc, item):
         -------
         new_index : Index
         """
-
         # try to convert if possible
         if _is_convertible_to_td(item):
             try:
                 item = Timedelta(item)
             except Exception:
                 pass
+        elif lib.checknull(item):
+            # GH 18295
+            item = self._na_value
 
         freq = None
-        if isinstance(item, Timedelta) or item is NaT:
+        if isinstance(item, Timedelta) or (item is self._na_value):
 
             # check freq can be preserved on edge cases
             if self.freq is not None:

pandas/tests/indexes/datetimes/test_indexing.py

@@ -145,6 +145,13 @@ def test_insert(self):
                 assert result.tz == expected.tz
                 assert result.freq is None
 
+        # GH 18295 (test missing)
+        expected = DatetimeIndex(
+            ['20170101', pd.NaT, '20170102', '20170103', '20170104'])
+        for na in (np.nan, pd.NaT, None):
+            result = date_range('20170101', periods=4).insert(1, na)
+            tm.assert_index_equal(result, expected)
+
     def test_delete(self):
         idx = date_range(start='2000-01-01', periods=5, freq='M', name='idx')
 

pandas/tests/indexes/period/test_period.py

@@ -706,3 +706,11 @@ def test_join_self(self, how):
         index = period_range('1/1/2000', periods=10)
         joined = index.join(index, how=how)
         assert index is joined
+
+    def test_insert(self):
+        # GH 18295 (test missing)
+        expected = PeriodIndex(
+            ['2017Q1', pd.NaT, '2017Q2', '2017Q3', '2017Q4'], freq='Q')
+        for na in (np.nan, pd.NaT, None):
+            result = period_range('2017Q1', periods=4, freq='Q').insert(1, na)
+            tm.assert_index_equal(result, expected)

pandas/tests/indexes/test_base.py

@@ -442,6 +442,12 @@ def test_insert(self):
         null_index = Index([])
         tm.assert_index_equal(Index(['a']), null_index.insert(0, 'a'))
 
+        # GH 18295 (test missing)
+        expected = Index(['a', np.nan, 'b', 'c'])
+        for na in (np.nan, pd.NaT, None):
+            result = Index(list('abc')).insert(1, na)
+            tm.assert_index_equal(result, expected)
+
     def test_delete(self):
         idx = Index(['a', 'b', 'c', 'd'], name='idx')
 

pandas/tests/indexes/test_category.py

@@ -353,6 +353,12 @@ def test_insert(self):
         # invalid
         pytest.raises(TypeError, lambda: ci.insert(0, 'd'))
 
+        # GH 18295 (test missing)
+        expected = CategoricalIndex(['a', np.nan, 'a', 'b', 'c', 'b'])
+        for na in (np.nan, pd.NaT, None):
+            result = CategoricalIndex(list('aabcb')).insert(1, na)
+            tm.assert_index_equal(result, expected)
+
     def test_delete(self):
 
         ci = self.create_index()

pandas/tests/indexes/test_interval.py

@@ -246,38 +246,50 @@ def test_delete(self):
         actual = self.index.delete(0)
         assert expected.equals(actual)
 
-    def test_insert(self):
-        expected = IntervalIndex.from_breaks(range(4))
-        actual = self.index.insert(2, Interval(2, 3))
-        assert expected.equals(actual)
-
-        pytest.raises(ValueError, self.index.insert, 0, 1)
-        pytest.raises(ValueError, self.index.insert, 0,
-                      Interval(2, 3, closed='left'))
-
     @pytest.mark.parametrize('data', [
-        interval_range(0, periods=10),
-        interval_range(1.7, periods=8, freq=2.5),
-        interval_range(Timestamp('20170101'), periods=12),
-        interval_range(Timedelta('1 day'), periods=6),
+        interval_range(0, periods=10, closed='neither'),
+        interval_range(1.7, periods=8, freq=2.5, closed='both'),
+        interval_range(Timestamp('20170101'), periods=12, closed='left'),
+        interval_range(Timedelta('1 day'), periods=6, closed='right'),
         IntervalIndex.from_tuples([('a', 'd'), ('e', 'j'), ('w', 'z')]),
         IntervalIndex.from_tuples([(1, 2), ('a', 'z'), (3.14, 6.28)])])
-    def test_insert_na(self, data):
-        # GH 18295
-        valid_na, invalid_na = np.nan, pd.NaT
-        if data.left._na_value is pd.NaT:
-            valid_na, invalid_na = invalid_na, valid_na
-
-        # valid insertion
-        expected = IntervalIndex([data[0], np.nan]).append(data[1:])
-        result = data.insert(1, valid_na)
+    def test_insert(self, data):
+        item = data[0]
+        idx_item = IntervalIndex([item], closed=data.closed)
+
+        # start
+        expected = idx_item.append(data)
+        result = data.insert(0, item)
         tm.assert_index_equal(result, expected)
 
-        # invalid insertion
-        msg = ('cannot insert with incompatible NA value: got {invalid}, '
-               'expected {valid}').format(invalid=invalid_na, valid=valid_na)
-        with tm.assert_raises_regex(TypeError, msg):
-            data.insert(1, invalid_na)
+        # end
+        expected = data.append(idx_item)
+        result = data.insert(len(data), item)
+        tm.assert_index_equal(result, expected)
+
+        # mid
+        expected = data[:3].append(idx_item).append(data[3:])
+        result = data.insert(3, item)
+        tm.assert_index_equal(result, expected)
+
+        # invalid type
+        msg = 'can only insert Interval objects and NA into an IntervalIndex'
+        with tm.assert_raises_regex(ValueError, msg):
+            data.insert(1, 'foo')
+
+        # invalid closed
+        msg = 'inserted item must be closed on the same side as the index'
+        for closed in {'left', 'right', 'both', 'neither'} - {item.closed}:
+            with tm.assert_raises_regex(ValueError, msg):
+                bad_item = Interval(item.left, item.right, closed=closed)
+                data.insert(1, bad_item)
+
+        # GH 18295 (test missing)
+        na_idx = IntervalIndex([np.nan], closed=data.closed)
+        for na in (np.nan, pd.NaT, None):
+            expected = data[:1].append(na_idx).append(data[1:])
+            result = data.insert(1, na)
+            tm.assert_index_equal(result, expected)
 
     def test_take(self):
         actual = self.index.take([0, 1])

pandas/tests/indexes/test_numeric.py

@@ -175,6 +175,13 @@ def test_modulo(self):
         expected = Index(index.values % 2)
         tm.assert_index_equal(index % 2, expected)
 
+    def test_insert(self):
+        # GH 18295 (test missing)
+        expected = Float64Index([0, np.nan, 1, 2, 3, 4])
+        for na in (np.nan, pd.NaT, None):
+            result = self.create_index().insert(1, na)
+            tm.assert_index_equal(result, expected)
+
 
 class TestFloat64Index(Numeric):
     _holder = Float64Index
@@ -1206,3 +1213,10 @@ def test_join_outer(self):
         tm.assert_index_equal(res, eres)
         tm.assert_numpy_array_equal(lidx, elidx)
         tm.assert_numpy_array_equal(ridx, eridx)
+
+    def test_insert(self):
+        # GH 18295 (test missing)
+        expected = UInt64Index([0, 0, 1, 2, 3, 4])
+        for na in (np.nan, pd.NaT, None):
+            result = self.create_index().insert(1, na)
+            tm.assert_index_equal(result, expected)

pandas/tests/indexes/test_range.py

@@ -295,6 +295,12 @@ def test_insert(self):
         # test 0th element
         tm.assert_index_equal(idx[0:4], result.insert(0, idx[0]))
 
+        # GH 18295 (test missing)
+        expected = Float64Index([0, np.nan, 1, 2, 3, 4])
+        for na in (np.nan, pd.NaT, None):
+            result = RangeIndex(5).insert(1, na)
+            tm.assert_index_equal(result, expected)
+
     def test_delete(self):
 
         idx = RangeIndex(5, name='Foo')

pandas/tests/indexes/timedeltas/test_indexing.py

@@ -57,6 +57,12 @@ def test_insert(self):
             assert result.name == expected.name
             assert result.freq == expected.freq
 
+        # GH 18295 (test missing)
+        expected = TimedeltaIndex(['1day', pd.NaT, '2day', '3day'])
+        for na in (np.nan, pd.NaT, None):
+            result = timedelta_range('1day', '3day').insert(1, na)
+            tm.assert_index_equal(result, expected)
+
     def test_delete(self):
         idx = timedelta_range(start='1 Days', periods=5, freq='D', name='idx')