COMPAT: followup to #17491 (#17503)

doc/source/whatsnew/v0.21.0.txt

@@ -190,19 +190,19 @@ the target. Now, a ``ValueError`` will be raised when such an input is passed in
 
 .. _whatsnew_0210.api_breaking.iteration_scalars:
 
-Iteration of Series/Index will now return python scalars
+Iteration of Series/Index will now return Python scalars
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Previously, when using certain iteration methods for a ``Series`` with dtype ``int`` or ``float``, you would receive a ``numpy`` scalar, e.g. a ``np.int64``, rather than a python ``int``. Issue (:issue:`10904`) corrected this for ``Series.tolist()`` and ``list(Series)``. This change makes all iteration methods consistent, in particular, for ``__iter__()`` and ``.map()``; note that this only affect int/float dtypes. (:issue:`13236`, :issue:`13258`, :issue:`14216`).
+Previously, when using certain iteration methods for a ``Series`` with dtype ``int`` or ``float``, you would receive a ``numpy`` scalar, e.g. a ``np.int64``, rather than a Python ``int``. Issue (:issue:`10904`) corrected this for ``Series.tolist()`` and ``list(Series)``. This change makes all iteration methods consistent, in particular, for ``__iter__()`` and ``.map()``; note that this only affects int/float dtypes. (:issue:`13236`, :issue:`13258`, :issue:`14216`).
 
 .. ipython:: python
 
-   s = Series([1, 2, 3])
+   s = pd.Series([1, 2, 3])
    s
 
 Previously:
 
-.. code-block:: python
+.. code-block:: ipython
 
    In [2]: type(list(s)[0])
    Out[2]: numpy.int64
@@ -215,14 +215,14 @@ New Behaviour:
 
 Furthermore this will now correctly box the results of iteration for :func:`DataFrame.to_dict` as well.
 
-.. ipython:: python
+.. ipython:: ipython
 
    d = {'a':[1], 'b':['b']}
-   df = DataFrame(d)
+   df = pd,DataFrame(d)
 
 Previously:
 
-.. code-block:: python
+.. code-block:: ipython
 
    In [8]: type(df.to_dict()['a'][0])
    Out[8]: numpy.int64

pandas/core/base.py

@@ -892,18 +892,31 @@ def argmin(self, axis=None):
 
     def tolist(self):
         """
-        return a list of the values; box to scalars
+        Return a list of the values.
+
+        These are each a scalar type, which is a Python scalar
+        (for str, int, float) or a pandas scalar
+        (for Timestamp/Timedelta/Interval/Period)
+
+        See Also
+        --------
+        numpy.tolist
         """
-        return list(self.__iter__())
+
+        if is_datetimelike(self):
+            return [_maybe_box_datetimelike(x) for x in self._values]
+        else:
+            return self._values.tolist()
 
     def __iter__(self):
         """
-        provide iteration over the values; box to scalars
+        Return an iterator of the values.
+
+        These are each a scalar type, which is a Python scalar
+        (for str, int, float) or a pandas scalar
+        (for Timestamp/Timedelta/Interval/Period)
         """
-        if is_datetimelike(self):
-            return (_maybe_box_datetimelike(x) for x in self._values)
-        else:
-            return iter(self._values.tolist())
+        return iter(self.tolist())
 
     @cache_readonly
     def hasnans(self):

pandas/core/categorical.py

@@ -26,7 +26,7 @@
     is_integer_dtype, is_bool,
     is_list_like, is_sequence,
     is_scalar)
-from pandas.core.common import is_null_slice
+from pandas.core.common import is_null_slice, _maybe_box_datetimelike
 
 from pandas.core.algorithms import factorize, take_1d, unique1d
 from pandas.core.base import (PandasObject, PandasDelegate,
@@ -401,8 +401,14 @@ def itemsize(self):
 
     def tolist(self):
         """
-        return a list of my values
+        Return a list of the values.
+
+        These are each a scalar type, which is a Python scalar
+        (for str, int, float) or a pandas scalar
+        (for Timestamp/Timedelta/Interval/Period)
         """
+        if is_datetimelike(self.categories):
+            return [_maybe_box_datetimelike(x) for x in self]
         return np.array(self).tolist()
 
     def reshape(self, new_shape, *args, **kwargs):

pandas/core/indexes/category.py

@@ -251,9 +251,8 @@ def get_values(self):
         """ return the underlying data as an ndarray """
         return self._data.get_values()
 
-    def __iter__(self):
-        """ iterate like Categorical """
-        return self._data.__iter__()
+    def tolist(self):
+        return self._data.tolist()
 
     @property
     def codes(self):

pandas/tests/indexes/test_category.py

@@ -576,12 +576,13 @@ def test_isin(self):
             ci.isin(['c', 'a', 'b', np.nan]), np.array([True] * 6))
 
         # mismatched categorical -> coerced to ndarray so doesn't matter
-        tm.assert_numpy_array_equal(
-            ci.isin(ci.set_categories(list('abcdefghi'))), np.array([True] *
-                                                                    6))
-        tm.assert_numpy_array_equal(
-            ci.isin(ci.set_categories(list('defghi'))),
-            np.array([False] * 5 + [True]))
+        result = ci.isin(ci.set_categories(list('abcdefghi')))
+        expected = np.array([True] * 6)
+        tm.assert_numpy_array_equal(result, expected)
+
+        result = ci.isin(ci.set_categories(list('defghi')))
+        expected = np.array([False] * 5 + [True])
+        tm.assert_numpy_array_equal(result, expected)
 
     def test_identical(self):
 

pandas/tests/series/test_api.py

@@ -245,43 +245,6 @@ def test_iter(self):
         for i, val in enumerate(self.ts):
             assert val == self.ts[i]
 
-    def test_iter_box(self):
-        vals = [pd.Timestamp('2011-01-01'), pd.Timestamp('2011-01-02')]
-        s = pd.Series(vals)
-        assert s.dtype == 'datetime64[ns]'
-        for res, exp in zip(s, vals):
-            assert isinstance(res, pd.Timestamp)
-            assert res.tz is None
-            assert res == exp
-
-        vals = [pd.Timestamp('2011-01-01', tz='US/Eastern'),
-                pd.Timestamp('2011-01-02', tz='US/Eastern')]
-        s = pd.Series(vals)
-
-        assert s.dtype == 'datetime64[ns, US/Eastern]'
-        for res, exp in zip(s, vals):
-            assert isinstance(res, pd.Timestamp)
-            assert res.tz == exp.tz
-            assert res == exp
-
-        # timedelta
-        vals = [pd.Timedelta('1 days'), pd.Timedelta('2 days')]
-        s = pd.Series(vals)
-        assert s.dtype == 'timedelta64[ns]'
-        for res, exp in zip(s, vals):
-            assert isinstance(res, pd.Timedelta)
-            assert res == exp
-
-        # period (object dtype, not boxed)
-        vals = [pd.Period('2011-01-01', freq='M'),
-                pd.Period('2011-01-02', freq='M')]
-        s = pd.Series(vals)
-        assert s.dtype == 'object'
-        for res, exp in zip(s, vals):
-            assert isinstance(res, pd.Period)
-            assert res.freq == 'M'
-            assert res == exp
-
     def test_keys(self):
         # HACK: By doing this in two stages, we avoid 2to3 wrapping the call
         # to .keys() in a list()

pandas/tests/test_base.py

@@ -1054,10 +1054,7 @@ class TestToIterable(object):
         ('timedelta64[ns]', Timedelta)]
 
     @pytest.mark.parametrize(
-        'dtype, rdtype',
-        dtypes + [
-            ('object', object),
-            ('category', object)])
+        'dtype, rdtype', dtypes)
     @pytest.mark.parametrize(
         'method',
         [
@@ -1074,6 +1071,43 @@ def test_iterable(self, typ, method, dtype, rdtype):
         result = method(s)[0]
         assert isinstance(result, rdtype)
 
+    @pytest.mark.parametrize(
+        'dtype, rdtype, obj',
+        [
+            ('object', object, 'a'),
+            ('object', (int, long), 1),
+            ('category', object, 'a'),
+            ('category', (int, long), 1)])
+    @pytest.mark.parametrize(
+        'method',
+        [
+            lambda x: x.tolist(),
+            lambda x: list(x),
+            lambda x: list(x.__iter__()),
+        ], ids=['tolist', 'list', 'iter'])
+    @pytest.mark.parametrize('typ', [Series, Index])
+    def test_iterable_object_and_category(self, typ, method,
+                                          dtype, rdtype, obj):
+        # gh-10904
+        # gh-13258
+        # coerce iteration to underlying python / pandas types
+        s = typ([obj], dtype=dtype)
+        result = method(s)[0]
+        assert isinstance(result, rdtype)
+
+    @pytest.mark.parametrize(
+        'dtype, rdtype', dtypes)
+    def test_iterable_items(self, dtype, rdtype):
+        # gh-13258
+        # test items / iteritems yields the correct boxed scalars
+        # this only applies to series
+        s = Series([1], dtype=dtype)
+        _, result = list(s.items())[0]
+        assert isinstance(result, rdtype)
+
+        _, result = list(s.iteritems())[0]
+        assert isinstance(result, rdtype)
+
     @pytest.mark.parametrize(
         'dtype, rdtype',
         dtypes + [
@@ -1102,3 +1136,40 @@ def test_categorial_datetimelike(self, method):
 
         result = method(i)[0]
         assert isinstance(result, Timestamp)
+
+    def test_iter_box(self):
+        vals = [pd.Timestamp('2011-01-01'), pd.Timestamp('2011-01-02')]
+        s = pd.Series(vals)
+        assert s.dtype == 'datetime64[ns]'
+        for res, exp in zip(s, vals):
+            assert isinstance(res, pd.Timestamp)
+            assert res.tz is None
+            assert res == exp
+
+        vals = [pd.Timestamp('2011-01-01', tz='US/Eastern'),
+                pd.Timestamp('2011-01-02', tz='US/Eastern')]
+        s = pd.Series(vals)
+
+        assert s.dtype == 'datetime64[ns, US/Eastern]'
+        for res, exp in zip(s, vals):
+            assert isinstance(res, pd.Timestamp)
+            assert res.tz == exp.tz
+            assert res == exp
+
+        # timedelta
+        vals = [pd.Timedelta('1 days'), pd.Timedelta('2 days')]
+        s = pd.Series(vals)
+        assert s.dtype == 'timedelta64[ns]'
+        for res, exp in zip(s, vals):
+            assert isinstance(res, pd.Timedelta)
+            assert res == exp
+
+        # period (object dtype, not boxed)
+        vals = [pd.Period('2011-01-01', freq='M'),
+                pd.Period('2011-01-02', freq='M')]
+        s = pd.Series(vals)
+        assert s.dtype == 'object'
+        for res, exp in zip(s, vals):
+            assert isinstance(res, pd.Period)
+            assert res.freq == 'M'
+            assert res == exp