BUG: fix empty prefix/suffix handling in pyarrow-backed string methods

pandas/core/arrays/_arrow_string_mixins.py

@@ -202,21 +202,37 @@ def _str_title(self) -> Self:
  def _str_swapcase(self) -> Self:
  return self._from_pyarrow_array(pc.utf8_swapcase(self._pa_array))
 
- def _str_removeprefix(self, prefix: str):
- if prefix == "":
- return self
- 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 self._from_pyarrow_array(result)
+def _str_removeprefix(self, prefix: str):
+ if prefix == "":
+ return self
+
+ 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 self._from_pyarrow_array(result)
+
+
+def _str_removesuffix(self, suffix: str):
+ if suffix == "":
+ return self
+
+ 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 self._from_pyarrow_array(result)
 
- def _str_removesuffix(self, suffix: str):
- if suffix == "":
- return self
- 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 self._from_pyarrow_array(result)
 
 
  def _str_startswith(