PERF: improve conversion to BooleanArray from int/float array (#30095)

Author: Yu Wang

asv_bench/benchmarks/array.py

@@ -0,0 +1,23 @@
+import numpy as np
+
+import pandas as pd
+
+
+class BooleanArray:
+    def setup(self):
+        self.values_bool = np.array([True, False, True, False])
+        self.values_float = np.array([1.0, 0.0, 1.0, 0.0])
+        self.values_integer = np.array([1, 0, 1, 0])
+        self.values_integer_like = [1, 0, 1, 0]
+
+    def time_from_bool_array(self):
+        pd.array(self.values_bool, dtype="boolean")
+
+    def time_from_integer_array(self):
+        pd.array(self.values_integer, dtype="boolean")
+
+    def time_from_integer_like(self):
+        pd.array(self.values_integer_like, dtype="boolean")
+
+    def time_from_float_array(self):
+        pd.array(self.values_float, dtype="boolean")

doc/source/whatsnew/v1.0.0.rst

@@ -156,7 +156,7 @@ type dedicated to boolean data that can hold missing values. With the default
 ``'bool`` data type based on a numpy bool array, the column can only hold
 True or False values and not missing values. This new :class:`BooleanDtype`
 can store missing values as well by keeping track of this in a separate mask.
-(:issue:`29555`)
+(:issue:`29555`, :issue:`30095`)
 
 .. ipython:: python
 

pandas/core/arrays/boolean.py

@@ -17,6 +17,7 @@
     is_integer,
     is_integer_dtype,
     is_list_like,
+    is_numeric_dtype,
     is_scalar,
     pandas_dtype,
 )
@@ -130,9 +131,19 @@ def coerce_to_array(values, mask=None, copy: bool = False):
     if isinstance(values, np.ndarray) and values.dtype == np.bool_:
         if copy:
             values = values.copy()
+    elif isinstance(values, np.ndarray) and is_numeric_dtype(values.dtype):
+        mask_values = isna(values)
+
+        values_bool = np.zeros(len(values), dtype=bool)
+        values_bool[~mask_values] = values[~mask_values].astype(bool)
+
+        if not np.all(
+            values_bool[~mask_values].astype(values.dtype) == values[~mask_values]
+        ):
+            raise TypeError("Need to pass bool-like values")
+
+        values = values_bool
     else:
-        # TODO conversion from integer/float ndarray can be done more efficiently
-        #  (avoid roundtrip through object)
         values_object = np.asarray(values, dtype=object)
 
         inferred_dtype = lib.infer_dtype(values_object, skipna=True)

pandas/tests/arrays/test_boolean.py

@@ -124,6 +124,8 @@ def test_to_boolean_array_missing_indicators(a, b):
         [1.0, 2.0],
         pd.date_range("20130101", periods=2),
         np.array(["foo"]),
+        np.array([1, 2]),
+        np.array([1.0, 2.0]),
         [np.nan, {"a": 1}],
     ],
 )
@@ -133,24 +135,37 @@ def test_to_boolean_array_error(values):
         pd.array(values, dtype="boolean")
 
 
-def test_to_boolean_array_integer_like():
-    # integers of 0's and 1's
-    result = pd.array([1, 0, 1, 0], dtype="boolean")
+def test_to_boolean_array_from_integer_array():
+    result = pd.array(np.array([1, 0, 1, 0]), dtype="boolean")
     expected = pd.array([True, False, True, False], dtype="boolean")
     tm.assert_extension_array_equal(result, expected)
 
-    result = pd.array(np.array([1, 0, 1, 0]), dtype="boolean")
+    # with missing values
+    result = pd.array(np.array([1, 0, 1, None]), dtype="boolean")
+    expected = pd.array([True, False, True, None], dtype="boolean")
     tm.assert_extension_array_equal(result, expected)
 
+
+def test_to_boolean_array_from_float_array():
     result = pd.array(np.array([1.0, 0.0, 1.0, 0.0]), dtype="boolean")
+    expected = pd.array([True, False, True, False], dtype="boolean")
     tm.assert_extension_array_equal(result, expected)
 
     # with missing values
-    result = pd.array([1, 0, 1, None], dtype="boolean")
+    result = pd.array(np.array([1.0, 0.0, 1.0, np.nan]), dtype="boolean")
     expected = pd.array([True, False, True, None], dtype="boolean")
     tm.assert_extension_array_equal(result, expected)
 
-    result = pd.array(np.array([1.0, 0.0, 1.0, np.nan]), dtype="boolean")
+
+def test_to_boolean_array_integer_like():
+    # integers of 0's and 1's
+    result = pd.array([1, 0, 1, 0], dtype="boolean")
+    expected = pd.array([True, False, True, False], dtype="boolean")
+    tm.assert_extension_array_equal(result, expected)
+
+    # with missing values
+    result = pd.array([1, 0, 1, None], dtype="boolean")
+    expected = pd.array([True, False, True, None], dtype="boolean")
     tm.assert_extension_array_equal(result, expected)