restrict to numeric or boolean

Author: jorisvandenbossche

pandas/core/strings/accessor.py

@@ -29,9 +29,9 @@
     is_extension_array_dtype,
     is_integer,
     is_list_like,
+    is_numeric_dtype,
     is_object_dtype,
     is_re,
-    is_string_dtype,
 )
 from pandas.core.dtypes.dtypes import (
     ArrowDtype,
@@ -2525,8 +2525,8 @@ def get_dummies(
         """
         from pandas.core.frame import DataFrame
 
-        if is_string_dtype(dtype):
-            raise ValueError("string dtype not supported, please use a numeric dtype")
+        if dtype is not None and not (is_numeric_dtype(dtype) or is_bool_dtype(dtype)):
+            raise ValueError("Only numeric or boolean dtypes are supported for 'dtype'")
         # we need to cast to Series of strings as only that has all
         # methods available for making the dummies...
         result, name = self._data.array._str_get_dummies(sep, dtype)

pandas/tests/strings/test_get_dummies.py

@@ -93,7 +93,10 @@ def test_get_dummies_with_pyarrow_dtype(any_string_dtype, dtype):
 # GH#47872
 def test_get_dummies_with_str_dtype(any_string_dtype):
     s = Series(["a|b", "a|c", np.nan], dtype=any_string_dtype)
-    with pytest.raises(
-        ValueError, match="string dtype not supported, please use a numeric dtype"
-    ):
+
+    msg = "Only numeric or boolean dtypes are supported for 'dtype'"
+    with pytest.raises(ValueError, match=msg):
         s.str.get_dummies("|", dtype=str)
+
+    with pytest.raises(ValueError, match=msg):
+        s.str.get_dummies("|", dtype="datetime64[ns]")