Split fastpath IntegerArray constructor and general purpose constructor

Author: jorisvandenbossche

pandas/core/arrays/__init__.py

@@ -7,4 +7,4 @@
 from .period import PeriodArrayMixin  # noqa
 from .timedeltas import TimedeltaArrayMixin  # noqa
 from .integer import (  # noqa
-    IntegerArray, to_integer_array)
+    IntegerArray, integer_array)

pandas/core/arrays/integer.py

@@ -76,7 +76,7 @@ def construct_from_string(cls, string):
                         "'{}'".format(cls, string))
 
 
-def to_integer_array(values, dtype=None):
+def integer_array(values, dtype=None, copy=False):
     """
     Infer and return an integer array of the values.
 
@@ -94,7 +94,8 @@ def to_integer_array(values, dtype=None):
     ------
     TypeError if incompatible types
     """
-    return IntegerArray(values, dtype=dtype, copy=False)
+    values, mask = coerce_to_array(values, dtype=dtype, copy=copy)
+    return IntegerArray(values, mask)
 
 
 def safe_cast(values, dtype, copy):
@@ -206,7 +207,7 @@ class IntegerArray(ExtensionArray, ExtensionOpsMixin):
     def dtype(self):
         return _dtypes[str(self._data.dtype)]
 
-    def __init__(self, values, mask=None, dtype=None, copy=False):
+    def __init__(self, values, mask, copy=False):
         """
         Parameters
         ----------
@@ -219,25 +220,33 @@ def __init__(self, values, mask=None, dtype=None, copy=False):
         -------
         IntegerArray
         """
-        self._data, self._mask = coerce_to_array(
-            values, dtype=dtype, mask=mask, copy=copy)
+        if not (isinstance(values, np.ndarray)
+                and np.issubdtype(values.dtype, np.integer)):
+            raise TypeError("values should be integer numpy array")
+        if not (isinstance(mask, np.ndarray) and mask.dtype == np.bool_):
+            raise TypeError("mask should be boolean numpy array")
+
+        if copy:
+            values = values.copy()
+            mask = mask.copy()
+
+        self._data = values
+        self._mask = mask
 
     @classmethod
     def _from_sequence(cls, scalars, dtype=None, copy=False):
-        return cls(scalars, dtype=dtype, copy=copy)
+        return integer_array(scalars, dtype=dtype, copy=copy)
 
     @classmethod
     def _from_factorized(cls, values, original):
-        return cls(values, dtype=original.dtype)
+        return integer_array(values, dtype=original.dtype)
 
     def __getitem__(self, item):
         if is_integer(item):
             if self._mask[item]:
                 return self.dtype.na_value
             return self._data[item]
-        return type(self)(self._data[item],
-                          mask=self._mask[item],
-                          dtype=self.dtype)
+        return type(self)(self._data[item], self._mask[item])
 
     def _coerce_to_ndarray(self):
         """
@@ -294,7 +303,7 @@ def take(self, indexer, allow_fill=False, fill_value=None):
             result[fill_mask] = fill_value
             mask = mask ^ fill_mask
 
-        return type(self)(result, mask=mask, dtype=self.dtype, copy=False)
+        return type(self)(result, mask, copy=False)
 
     def copy(self, deep=False):
         data, mask = self._data, self._mask
@@ -304,7 +313,7 @@ def copy(self, deep=False):
         else:
             data = data.copy()
             mask = mask.copy()
-        return type(self)(data, mask, dtype=self.dtype, copy=False)
+        return type(self)(data, mask, copy=False)
 
     def __setitem__(self, key, value):
         _is_scalar = is_scalar(value)
@@ -356,7 +365,7 @@ def _na_value(self):
     def _concat_same_type(cls, to_concat):
         data = np.concatenate([x._data for x in to_concat])
         mask = np.concatenate([x._mask for x in to_concat])
-        return cls(data, mask=mask, dtype=to_concat[0].dtype)
+        return cls(data, mask)
 
     def astype(self, dtype, copy=True):
         """Cast to a NumPy array or IntegerArray with 'dtype'.
@@ -386,8 +395,7 @@ def astype(self, dtype, copy=True):
         if isinstance(dtype, _IntegerDtype):
             result = self._data.astype(dtype.numpy_dtype,
                                        casting='same_kind', copy=False)
-            return type(self)(result, mask=self._mask,
-                              dtype=dtype, copy=False)
+            return type(self)(result, mask=self._mask, copy=False)
 
         # coerce
         data = self._coerce_to_ndarray()
@@ -523,7 +531,7 @@ def _maybe_mask_result(self, result, mask, other, op_name):
             result[mask] = np.nan
             return result
 
-        return type(self)(result, mask=mask, dtype=self.dtype, copy=False)
+        return type(self)(result, mask, copy=False)
 
     @classmethod
     def _create_arithmetic_method(cls, op):

pandas/core/indexes/base.py

@@ -280,7 +280,7 @@ def __new__(cls, data=None, dtype=None, copy=False, name=None,
             if not (dtype is None or is_object_dtype(dtype)):
 
                 # coerce to the provided dtype
-                data = dtype.construct_array_type()(
+                data = dtype.construct_array_type()._from_sequence(
                     data, dtype=dtype, copy=False)
 
             # coerce to the object dtype

pandas/core/series.py

@@ -4095,7 +4095,7 @@ def _try_cast(arr, take_fast_path):
                                      ordered=dtype.ordered)
             elif is_extension_array_dtype(dtype):
                 # create an extension array from its dtype
-                array_type = dtype.construct_array_type()
+                array_type = dtype.construct_array_type()._from_sequence
                 subarr = array_type(subarr, dtype=dtype, copy=copy)
 
             elif dtype is not None and raise_cast_failure:

pandas/tests/extension/base/missing.py

@@ -94,7 +94,7 @@ def test_fillna_series_method(self, data_missing, method):
         fill_value = data_missing[1]
 
         if method == 'ffill':
-            data_missing = type(data_missing)(data_missing[::-1])
+            data_missing = data_missing[::-1]
 
         result = pd.Series(data_missing).fillna(method=method)
         expected = pd.Series(

pandas/tests/extension/integer/test_integer.py

@@ -9,7 +9,7 @@
 from pandas.core.dtypes.generic import ABCIndexClass
 
 from pandas.core.arrays import (
-    to_integer_array, IntegerArray)
+    integer_array, IntegerArray)
 from pandas.core.arrays.integer import (
     Int8Dtype, Int16Dtype, Int32Dtype, Int64Dtype,
     UInt8Dtype, UInt16Dtype, UInt32Dtype, UInt64Dtype)
@@ -31,12 +31,12 @@ def dtype(request):
 
 @pytest.fixture
 def data(dtype):
-    return IntegerArray(make_data(), dtype=dtype)
+    return integer_array(make_data(), dtype=dtype)
 
 
 @pytest.fixture
 def data_missing(dtype):
-    return IntegerArray([np.nan, 1], dtype=dtype)
+    return integer_array([np.nan, 1], dtype=dtype)
 
 
 @pytest.fixture
@@ -49,12 +49,12 @@ def gen(count):
 
 @pytest.fixture
 def data_for_sorting(dtype):
-    return IntegerArray([1, 2, 0], dtype=dtype)
+    return integer_array([1, 2, 0], dtype=dtype)
 
 
 @pytest.fixture
 def data_missing_for_sorting(dtype):
-    return IntegerArray([1, np.nan, 0], dtype=dtype)
+    return integer_array([1, np.nan, 0], dtype=dtype)
 
 
 @pytest.fixture
@@ -74,7 +74,7 @@ def data_for_grouping(dtype):
     a = 0
     c = 2
     na = np.nan
-    return IntegerArray([b, b, na, na, a, a, b, c], dtype=dtype)
+    return integer_array([b, b, na, na, a, a, b, c], dtype=dtype)
 
 
 def test_dtypes(dtype):
@@ -494,8 +494,7 @@ def test_construct_index(self, all_data, dropna):
         else:
             other = all_data
 
-        result = pd.Index(IntegerArray(other,
-                                       dtype=all_data.dtype))
+        result = pd.Index(integer_array(other, dtype=all_data.dtype))
         expected = pd.Index(other, dtype=object)
 
         self.assert_index_equal(result, expected)
@@ -584,14 +583,14 @@ def test_construct_cast_invalid(self, dtype):
         msg = "cannot safely"
         arr = [1.2, 2.3, 3.7]
         with tm.assert_raises_regex(TypeError, msg):
-            IntegerArray(arr, dtype=dtype)
+            integer_array(arr, dtype=dtype)
 
         with tm.assert_raises_regex(TypeError, msg):
             pd.Series(arr).astype(dtype)
 
         arr = [1.2, 2.3, 3.7, np.nan]
         with tm.assert_raises_regex(TypeError, msg):
-            IntegerArray(arr, dtype=dtype)
+            integer_array(arr, dtype=dtype)
 
         with tm.assert_raises_regex(TypeError, msg):
             pd.Series(arr).astype(dtype)
@@ -658,7 +657,7 @@ def test_conversions(data_missing):
 def test_to_integer_array_error(values):
     # error in converting existing arrays to IntegerArrays
     with pytest.raises(TypeError):
-        to_integer_array(values)
+        integer_array(values)
 
 
 @pytest.mark.parametrize(
@@ -669,8 +668,8 @@ def test_to_integer_array_error(values):
         (np.array([1, np.nan]), 'int8', Int8Dtype)])
 def test_to_integer_array(values, to_dtype, result_dtype):
     # convert existing arrays to IntegerArrays
-    result = to_integer_array(values, dtype=to_dtype)
-    expected = IntegerArray(values, dtype=result_dtype())
+    result = integer_array(values, dtype=to_dtype)
+    expected = integer_array(values, dtype=result_dtype())
     tm.assert_extension_array_equal(result, expected)