REF: get rid of ArrowStringArrayNumpySemantics (#62165)

Author: jbrockmendel

pandas/core/arrays/_arrow_string_mixins.py

@@ -34,6 +34,9 @@ class ArrowStringArrayMixin:
  def __init__(self, *args, **kwargs) -> None:
  raise NotImplementedError
 
+ def _from_pyarrow_array(self, pa_array) -> Self:
+ raise NotImplementedError
+
  def _convert_bool_result(self, result, na=lib.no_default, method_name=None):
  # Convert a bool-dtype result to the appropriate result type
  raise NotImplementedError
@@ -50,31 +53,31 @@ def _str_len(self):
  return self._convert_int_result(result)
 
  def _str_lower(self) -> Self:
- return type(self)(pc.utf8_lower(self._pa_array))
+ return self._from_pyarrow_array(pc.utf8_lower(self._pa_array))
 
  def _str_upper(self) -> Self:
- return type(self)(pc.utf8_upper(self._pa_array))
+ return self._from_pyarrow_array(pc.utf8_upper(self._pa_array))
 
  def _str_strip(self, to_strip=None) -> Self:
  if to_strip is None:
  result = pc.utf8_trim_whitespace(self._pa_array)
  else:
  result = pc.utf8_trim(self._pa_array, characters=to_strip)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_lstrip(self, to_strip=None) -> Self:
  if to_strip is None:
  result = pc.utf8_ltrim_whitespace(self._pa_array)
  else:
  result = pc.utf8_ltrim(self._pa_array, characters=to_strip)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_rstrip(self, to_strip=None) -> Self:
  if to_strip is None:
  result = pc.utf8_rtrim_whitespace(self._pa_array)
  else:
  result = pc.utf8_rtrim(self._pa_array, characters=to_strip)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_pad(
  self,
@@ -104,7 +107,9 @@ def _str_pad(
  raise ValueError(
  f"Invalid side: {side}. Side must be one of 'left', 'right', 'both'"
  )
- return type(self)(pa_pad(self._pa_array, width=width, padding=fillchar))
+ return self._from_pyarrow_array(
+ pa_pad(self._pa_array, width=width, padding=fillchar)
+ )
 
  def _str_get(self, i: int) -> Self:
  lengths = pc.utf8_length(self._pa_array)
@@ -124,15 +129,17 @@ def _str_get(self, i: int) -> Self:
  )
  null_value = pa.scalar(None, type=self._pa_array.type)
  result = pc.if_else(not_out_of_bounds, selected, null_value)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_slice(
  self, start: int | None = None, stop: int | None = None, step: int | None = None
  ) -> Self:
  if pa_version_under13p0:
  # GH#59724
  result = self._apply_elementwise(lambda val: val[start:stop:step])
- return type(self)(pa.chunked_array(result, type=self._pa_array.type))
+ return self._from_pyarrow_array(
+ pa.chunked_array(result, type=self._pa_array.type)
+ )
  if start is None:
  if step is not None and step < 0:
  # GH#59710
@@ -141,7 +148,7 @@ def _str_slice(
  start = 0
  if step is None:
  step = 1
- return type(self)(
+ return self._from_pyarrow_array(
  pc.utf8_slice_codeunits(self._pa_array, start=start, stop=stop, step=step)
  )
 
@@ -154,7 +161,9 @@ def _str_slice_replace(
  start = 0
  if stop is None:
  stop = np.iinfo(np.int64).max
- return type(self)(pc.utf8_replace_slice(self._pa_array, start, stop, repl))
+ return self._from_pyarrow_array(
+ pc.utf8_replace_slice(self._pa_array, start, stop, repl)
+ )
 
  def _str_replace(
  self,
@@ -181,32 +190,32 @@ def _str_replace(
  replacement=repl,
  max_replacements=pa_max_replacements,
  )
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_capitalize(self) -> Self:
- return type(self)(pc.utf8_capitalize(self._pa_array))
+ return self._from_pyarrow_array(pc.utf8_capitalize(self._pa_array))
 
  def _str_title(self) -> Self:
- return type(self)(pc.utf8_title(self._pa_array))
+ return self._from_pyarrow_array(pc.utf8_title(self._pa_array))
 
  def _str_swapcase(self) -> Self:
- return type(self)(pc.utf8_swapcase(self._pa_array))
+ return self._from_pyarrow_array(pc.utf8_swapcase(self._pa_array))
 
  def _str_removeprefix(self, prefix: str):
  if not pa_version_under13p0:
  starts_with = pc.starts_with(self._pa_array, pattern=prefix)
  removed = pc.utf8_slice_codeunits(self._pa_array, len(prefix))
  result = pc.if_else(starts_with, removed, self._pa_array)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
  predicate = lambda val: val.removeprefix(prefix)
  result = self._apply_elementwise(predicate)
- return type(self)(pa.chunked_array(result))
+ return self._from_pyarrow_array(pa.chunked_array(result))
 
  def _str_removesuffix(self, suffix: str):
  ends_with = pc.ends_with(self._pa_array, pattern=suffix)
  removed = pc.utf8_slice_codeunits(self._pa_array, 0, stop=-len(suffix))
  result = pc.if_else(ends_with, removed, self._pa_array)
- return type(self)(result)
+ return self._from_pyarrow_array(result)
 
  def _str_startswith(
  self, pat: str | tuple[str, ...], na: Scalar | lib.NoDefault = lib.no_default