iabhi4 opened a new issue, #46683: URL: https://github.com/apache/arrow/issues/46683
### Describe the enhancement requested ### Feature Request There’s currently no `utf8_zfill` kernel in `pyarrow.compute`, so Python’s `str.zfill()` behavior can't be reproduced efficiently with Arrow arrays. While fixing [pandas-dev/pandas#61485](https://github.com/pandas-dev/pandas/issues/61485), I noticed `Series.str.zfill()` breaks when used on `ArrowDtype(pa.string())` because the backend expects a string-padding kernel like `utf8_rjust`, but nothing exists for zfill. For now, it has to fall back to element-wise Python ops which aren't ideal ### Reproduction ``` import pandas as pd import pyarrow as pa s = pd.Series(["A", "AB", "ABC"], dtype=pd.ArrowDtype(pa.string())) s.str.zfill(3) # Currently falls back to Python and works via slow path ``` ### Expected behavior would be `'A' → '00A'` `'AB' → '0AB'` `'ABC' → 'ABC'` (no change since it's already 3 chars) ### What we need A kernel like `pc.utf8_zfill(array, width)` that mimics Python’s `str.zfill()`: - Pad strings with '0' from the left to reach width - Optional enhancement: handle signs (+, -) same as Python ### Why it matters This will help pandas fully support `.str.zfill()` for Arrow-backed string arrays, similar to how `utf8_rjust`, `binary_join`, etc., already work natively. It'll avoid falling back to slower Python paths and ensure parity with standard Python string behavior ### Notes I’ve temporarily added a `TODO` in the pandas code to switch over once this is available. ### Component(s) Python -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@arrow.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
