more type annotations

Author: jorisvandenbossche

pandas/core/arrays/arrow/array.py

@@ -2383,7 +2383,7 @@ def _str_match(
         pat: str,
         case: bool = True,
         flags: int = 0,
-        na: Scalar | None = lib.no_default,
+        na: Scalar | lib.NoDefault = lib.no_default,
     ) -> Self:
         if not pat.startswith("^"):
             pat = f"^{pat}"

pandas/core/arrays/string_arrow.py

@@ -223,6 +223,7 @@ def insert(self, loc: int, item) -> ArrowStringArray:
 
     def _predicate_result_converter(self, values, na=lib.no_default):
         if self.dtype.na_value is np.nan:
+            na_value: bool | float | lib.NoDefault
             if na is lib.no_default:
                 na_value = False
             elif not isna(na):

pandas/core/strings/base.py

@@ -6,7 +6,7 @@
     Literal,
 )
 
-import numpy as np
+from pandas._libs import lib
 
 if TYPE_CHECKING:
     from collections.abc import (
@@ -88,7 +88,11 @@ def _str_repeat(self, repeats: int | Sequence[int]):
 
     @abc.abstractmethod
     def _str_match(
-        self, pat: str, case: bool = True, flags: int = 0, na: Scalar = np.nan
+        self,
+        pat: str,
+        case: bool = True,
+        flags: int = 0,
+        na: Scalar | lib.NoDefault = lib.no_default,
     ):
         pass
 
@@ -98,7 +102,7 @@ def _str_fullmatch(
         pat: str | re.Pattern,
         case: bool = True,
         flags: int = 0,
-        na: Scalar = np.nan,
+        na: Scalar | lib.NoDefault = lib.no_default,
     ):
         pass
 

pandas/core/strings/object_array.py

@@ -220,7 +220,11 @@ def rep(x, r):
             return type(self)._from_sequence(result, dtype=self.dtype)
 
     def _str_match(
-        self, pat: str, case: bool = True, flags: int = 0, na: Scalar | None = None
+        self,
+        pat: str,
+        case: bool = True,
+        flags: int = 0,
+        na: Scalar | lib.NoDefault = lib.no_default,
     ):
         if not case:
             flags |= re.IGNORECASE
@@ -235,7 +239,7 @@ def _str_fullmatch(
         pat: str | re.Pattern,
         case: bool = True,
         flags: int = 0,
-        na: Scalar | None = None,
+        na: Scalar | lib.NoDefault = lib.no_default,
     ):
         if not case:
             flags |= re.IGNORECASE