inference

Author: TomAugspurger

pandas/core/arrays/array_.py

@@ -1,5 +1,7 @@
 import numpy as np
 
+from pandas._libs import lib, tslibs
+
 from pandas.core.dtypes.common import is_extension_array_dtype
 from pandas.core.dtypes.dtypes import registry
 from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
@@ -56,6 +58,8 @@ def array(data, dtype=None, copy=False):
     [a, b, a]
     Categories (3, object): [a < b < c]
     """
+    from pandas.core.arrays import period_array
+
     if isinstance(data, (ABCSeries, ABCIndexClass)):
         data = data._values
 
@@ -66,4 +70,15 @@ def array(data, dtype=None, copy=False):
         cls = dtype.construct_array_type()
         return cls._from_sequence(data, dtype=dtype, copy=copy)
 
+    if dtype is None:
+        inferred_dtype = lib.infer_dtype(data)
+        if inferred_dtype == 'period':
+            try:
+                return period_array(data)
+            except tslibs.IncompatibleFrequency:
+                pass  # we return an array below.
+
+        # TODO(DatetimeArray): handle this type
+        # TODO(BooleanArray): handle this type
+
     return np.array(data, dtype=dtype, copy=copy)

pandas/tests/arrays/test_array.py

@@ -1,16 +1,16 @@
 import decimal
 
 import numpy as np
-import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
 from pandas.core.dtypes.dtypes import registry
+
+import pandas as pd
 from pandas.api.extensions import register_extension_dtype
-from pandas.core.arrays import period_array, integer_array
+from pandas.core.arrays import integer_array, period_array
 from pandas.tests.extension.decimal import (
-    to_decimal, DecimalArray, DecimalDtype
-)
+    DecimalArray, DecimalDtype, to_decimal)
+import pandas.util.testing as tm
+import pytest
 
 
 @pytest.mark.parametrize("data, dtype, expected", [
@@ -38,6 +38,22 @@ def test_array(data, dtype, expected):
     tm.assert_equal(result, expected)
 
 
+@pytest.mark.parametrize('data, expected', [
+    ([pd.Period("2000", "D"), pd.Period("2001", "D")],
+     period_array(["2000", "2001"], freq="D")),
+])
+def test_array_inference(data, expected):
+    result = pd.array(data)
+    tm.assert_equal(result, expected)
+
+
+def test_array_inference_period_fails():
+    data = [pd.Period("2000", "D"), pd.Period("2001", "A")]
+    result = pd.array(data)
+    expected = np.array(data, dtype=object)
+    tm.assert_numpy_array_equal(result, expected)
+
+
 # ---------------------------------------------------------------------------
 # A couple dummy classes to ensure that Series and Indexes are unboxed before
 # getting to the EA classes.