Fixes

Author: jschendel

pandas/compat/__init__.py

@@ -100,6 +100,10 @@ def signature(f):
                                            'varargs', 'keywords'])
         return argspec(args, defaults, varargs, keywords)
 
+    def _get_range_parameters(data):
+        """Gets the start, stop, and step parameters from a range object"""
+        return data.start, data.stop, data.step
+
     # have to explicitly put builtins into the namespace
     range = range
     map = map
@@ -146,6 +150,24 @@ def bytes_to_str(b, encoding='ascii'):
     def signature(f):
         return inspect.getargspec(f)
 
+    def _get_range_parameters(data):
+        """Gets the start, stop, and step parameters from a range object"""
+        # seems we only have indexing ops to infer
+        # rather than direct accessors
+        if len(data) > 1:
+            step = data[1] - data[0]
+            stop = data[-1] + step
+            start = data[0]
+        elif len(data):
+            start = data[0]
+            stop = data[0] + 1
+            step = 1
+        else:
+            start = stop = 0
+            step = 1
+
+        return start, stop, step
+
     # import iterator versions of these functions
     range = xrange
     intern = intern

pandas/core/common.py

@@ -552,30 +552,6 @@ class Sentinel(object):
     return Sentinel()
 
 
-def _get_range_parameters(data):
-    """Gets the start, stop, and step parameters from a range object"""
-    if compat.PY3:
-        step = data.step
-        stop = data.stop
-        start = data.start
-    else:
-        # seems we only have indexing ops to infer
-        # rather than direct accessors
-        if len(data) > 1:
-            step = data[1] - data[0]
-            stop = data[-1] + step
-            start = data[0]
-        elif len(data):
-            start = data[0]
-            stop = data[0] + 1
-            step = 1
-        else:
-            start = stop = 0
-            step = 1
-
-    return start, stop, step
-
-
 # ----------------------------------------------------------------------
 # Detect our environment
 

pandas/core/indexes/range.py

@@ -10,9 +10,9 @@
     is_int64_dtype)
 
 from pandas import compat
-from pandas.compat import lrange, range
+from pandas.compat import lrange, range, _get_range_parameters
 from pandas.compat.numpy import function as nv
-from pandas.core.common import _all_none, _get_range_parameters
+from pandas.core.common import _all_none
 from pandas.core.indexes.base import Index, _index_shared_docs
 from pandas.util._decorators import Appender, cache_readonly
 import pandas.core.dtypes.concat as _concat

pandas/core/series.py

@@ -46,8 +46,7 @@
                                 _maybe_box_datetimelike,
                                 _dict_compat,
                                 standardize_mapping,
-                                _any_none,
-                                _get_range_parameters)
+                                _any_none)
 from pandas.core.index import (Index, MultiIndex, InvalidIndexError,
                                Float64Index, _ensure_index)
 from pandas.core.indexing import check_bool_indexer, maybe_convert_indices
@@ -61,7 +60,8 @@
 from pandas.core.indexes.period import PeriodIndex
 from pandas import compat
 from pandas.io.formats.terminal import get_terminal_size
-from pandas.compat import zip, u, OrderedDict, StringIO
+from pandas.compat import (
+    zip, u, OrderedDict, StringIO, range, _get_range_parameters)
 from pandas.compat.numpy import function as nv
 
 from pandas.core import accessor
@@ -3181,12 +3181,8 @@ def _try_cast(arr, take_fast_path):
     elif isinstance(data, range):
         # GH 16804
         start, stop, step = _get_range_parameters(data)
-        if is_extension_type(dtype):
-            arr = np.arange(start, stop, step, dtype='int64')
-            subarr = _try_cast(arr, False)
-        else:
-            subarr = np.arange(start, stop, step, dtype=dtype or 'int64')
-
+        arr = np.arange(start, stop, step, dtype='int64')
+        subarr = _try_cast(arr, False)
     else:
         subarr = _try_cast(data, False)
 

pandas/tests/frame/test_constructors.py

@@ -1927,15 +1927,11 @@ def test_to_frame_with_falsey_names(self):
         result = DataFrame(Series(name=0)).dtypes
         tm.assert_series_equal(result, expected)
 
-    def test_constructor_range_dtype(self):
+    @pytest.mark.parametrize('dtype', [None, 'uint8', 'category'])
+    def test_constructor_range_dtype(self, dtype):
         # GH 16804
-        expected = DataFrame({'A': [0, 1, 2, 3, 4]}, dtype='int64')
-        result = DataFrame({'A': range(5)})
-        tm.assert_frame_equal(result, expected)
-
-        # override default dtype
-        expected = DataFrame({'A': [0, 1, 2, 3, 4]}, dtype='uint8')
-        result = DataFrame({'A': range(5)}, dtype='uint8')
+        expected = DataFrame({'A': [0, 1, 2, 3, 4]}, dtype=dtype or 'int64')
+        result = DataFrame({'A': range(5)}, dtype=dtype)
         tm.assert_frame_equal(result, expected)
 
 

pandas/tests/series/test_constructors.py

@@ -847,13 +847,9 @@ def test_constructor_generic_timestamp_deprecated(self):
         with tm.assert_raises_regex(TypeError, msg):
             Series([], dtype='M8[ps]')
 
-    def test_constructor_range_dtype(self):
+    @pytest.mark.parametrize('dtype', [None, 'uint8', 'category'])
+    def test_constructor_range_dtype(self, dtype):
         # GH 16804
-        expected = Series([0, 1, 2, 3, 4], dtype='int64')
-        result = Series(range(5))
-        tm.assert_series_equal(result, expected)
-
-        # override default dtype
-        expected = Series([0, 1, 2, 3, 4], dtype='uint8')
-        result = Series(range(5), dtype='uint8')
+        expected = Series([0, 1, 2, 3, 4], dtype=dtype or 'int64')
+        result = Series(range(5), dtype=dtype)
         tm.assert_series_equal(result, expected)

pandas/tests/test_common.py

@@ -7,7 +7,7 @@
 import numpy as np
 
 from pandas import Series, Timestamp
-from pandas.compat import range, lmap, PY2
+from pandas.compat import range, lmap
 import pandas.core.common as com
 import pandas.util.testing as tm
 
@@ -221,20 +221,3 @@ def test_standardize_mapping():
 
     dd = collections.defaultdict(list)
     assert isinstance(com.standardize_mapping(dd), partial)
-
-
-@pytest.mark.parametrize(
-    'start,stop,step', [(0, 10, 2), (11, -2, -1), (0, -5, 1), (2, 4, 8)])
-def test_get_range_parameters(start, stop, step):
-    rng = range(start, stop, step)
-    if PY2 and len(rng) == 0:
-        start_expected, stop_expected, step_expected = 0, 0, 1
-    elif PY2 and len(rng) == 1:
-        start_expected, stop_expected, step_expected = start, start + 1, 1
-    else:
-        start_expected, stop_expected, step_expected = start, stop, step
-
-    start_result, stop_result, step_result = com._get_range_parameters(rng)
-    assert start_result == start_expected
-    assert stop_result == stop_expected
-    assert step_result == step_expected

pandas/tests/test_compat.py

@@ -3,9 +3,10 @@
 Testing that functions from compat work as expected
 """
 
+import pytest
 from pandas.compat import (range, zip, map, filter, lrange, lzip, lmap,
                            lfilter, builtins, iterkeys, itervalues, iteritems,
-                           next)
+                           next, _get_range_parameters, PY2)
 
 
 class TestBuiltinIterators(object):
@@ -69,3 +70,22 @@ def test_dict_iterators(self):
         assert next(itervalues({1: 2})) == 2
         assert next(iterkeys({1: 2})) == 1
         assert next(iteritems({1: 2})) == (1, 2)
+
+
+class TestCompatFunctions(object):
+
+    @pytest.mark.parametrize(
+        'start,stop,step', [(0, 10, 2), (11, -2, -1), (0, -5, 1), (2, 4, 8)])
+    def test_get_range_parameters(self, start, stop, step):
+        rng = range(start, stop, step)
+        if PY2 and len(rng) == 0:
+            start_expected, stop_expected, step_expected = 0, 0, 1
+        elif PY2 and len(rng) == 1:
+            start_expected, stop_expected, step_expected = start, start + 1, 1
+        else:
+            start_expected, stop_expected, step_expected = start, stop, step
+
+        start_result, stop_result, step_result = _get_range_parameters(rng)
+        assert start_result == start_expected
+        assert stop_result == stop_expected
+        assert step_result == step_expected

pandas/tests/test_resample.py

@@ -3030,10 +3030,10 @@ def test_nearest(self):
         # GH 17496
         # Resample nearest
         index = pd.date_range('1/1/2000', periods=3, freq='T')
-        result = pd.Series(np.arange(3), index=index).resample('20s').nearest()
+        result = pd.Series(range(3), index=index).resample('20s').nearest()
 
         expected = pd.Series(
-            np.array([0, 0, 1, 1, 1, 2, 2]),
+            [0, 0, 1, 1, 1, 2, 2],
             index=pd.DatetimeIndex(
                 ['2000-01-01 00:00:00', '2000-01-01 00:00:20',
                  '2000-01-01 00:00:40', '2000-01-01 00:01:00',