# Polars 1.35.1 — Python Polars 1.35.1

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2025-10-30
- Version: 1.35.1
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.35.1
- Permalink: https://whatsnew.fyi/product/polars/releases/1.35.1

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Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **changed** — Don't recompute full rolling moment window when NaNs/nulls leave the window
- **changed** — Skip filtering scan IR if no paths were filtered
- **changed** — Optimize ipc stream read performance
- **added** — Support BYTE_ARRAY backed Decimals in Parquet
- **changed** — Allow glimpse to return a DataFrame
- **added** — Add allow_empty flag to item
- **fixed** — The SQL interface should use logical, not bitwise, behaviour for unary NOT operator
- **fixed** — Fix panic if scan predicate produces 0 length mask
- **fixed** — Ensure SQL table alias resolution checks against CTE aliases on fallback
- **fixed** — Fix panic in group_by_dynamic with group_by and multiple chunks
- **fixed** — Fix panic when using struct field as join key
- **fixed** — Allow broadcast in group_by for ApplyExpr and BinaryExpr
- **fixed** — Fix field metadata for nested categorical PyCapsule export
- **fixed** — Block predicate pushdown when group_by key values are changed
- **fixed** — Fix group-by aggregation problems caused by AmortSeries
- **fixed** — Don't push down predicates passed inserted cache nodes
- **fixed** — Allow for negative time in group_by_dynamic iterator
- **changed** — Change group length mismatch error to ShapeError

##### 🚀 Performance improvements

- Don't recompute full rolling moment window when NaNs/nulls leave the window (#25078)
- Skip filtering scan IR if no paths were filtered (#25037)
- Optimize ipc stream read performance (#24671)

##### ✨ Enhancements

- Support BYTE\_ARRAY backed Decimals in Parquet (#25076)
- Allow `glimpse` to return a `DataFrame` (#24803)
- Add `allow_empty` flag to `item` (#25048)

##### 🐞 Bug fixes

- The `SQL` interface should use logical, not bitwise, behaviour for unary "NOT" operator (#25091)
- Fix panic if scan predicate produces 0 length mask (#25089)
- Ensure SQL table alias resolution checks against CTE aliases on fallback (#25071)
- Panic in `group_by_dynamic` with `group_by` and multiple chunks (#25075)
- Minor improvement to internal `is_pycapsule` utility function (#25073)
- Fix panic when using struct field as join key (#25059)
- Allow broadcast in `group_by` for `ApplyExpr` and `BinaryExpr` (#25053)
- Fix field metadata for nested categorical PyCapsule export (#25052)
- Block predicate pushdown when `group_by` key values are changed (#25032)
- Group-By aggregation problems caused by `AmortSeries` (#25043)
- Don't push down predicates passed inserted cache nodes (#25042)
- Allow for negative time in `group_by_dynamic` iterator (#25041)

##### 📖 Documentation

- Fix typo in public dataset URL (#25044)

##### 🛠️ Other improvements

- Disable recursive CSPE for now (#25085)
- Change group length mismatch error to `ShapeError` (#25004)
- Update toolchain (#25007)

Thank you to all our contributors for making this release possible!
@Kevin-Patyk, @Liyixin95, @alexander-beedie, @coastalwhite, @kdn36, @nameexhaustion, @orlp, @r-brink, @ritchie46 and @stijnherfst