BUG: fix regex numeric group replacement in PyArrow string arrays

zishan044 · zishan044 · commit 80eeb6360b19 · 2025-10-11T17:27:24.000+06:00
diff --git a/pandas/core/arrays/_arrow_string_mixins.py b/pandas/core/arrays/_arrow_string_mixins.py
@@ -175,7 +175,7 @@ def _str_replace(
             or flags
             or (
                 isinstance(repl, str)
-                and (r"\g<" in repl or re.search(r"\\\d", repl) is not None)
+                and r"\g<" in repl  # Block named group references (\g<name>); numeric groups (\1) are supported by PyArrow
             )
         ):
             raise NotImplementedError(

Original file line number	Diff line number	Diff line change
`@@ -175,7 +175,7 @@ def _str_replace(`
`175`	`175`	`or flags`
`176`	`176`	`or (`
`177`	`177`	`isinstance(repl, str)`
`178`		`- and (r"\g<" in repl or re.search(r"\\\d", repl) is not None)`
	`178`	`+ and r"\g<" in repl # Block named group references (\g<name>); numeric groups (\1) are supported by PyArrow`
`179`	`179`	`)`
`180`	`180`	`):`
`181`	`181`	`raise NotImplementedError(`