# Polars 1.27.1 — Python Polars 1.27.1

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2025-04-11
- Version: 1.27.1
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.27.1
- Permalink: https://whatsnew.fyi/product/polars/releases/1.27.1

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

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** — Improved expression autocomplete for IPython, Jupyter, and Marimo
- **fixed** — Incorrect condition on empty inner join fast path
- **fixed** — Fallback predicate filter for min=max with is_in
- **fixed** — Don't panic for LruCachedFunc for size=0
- **fixed** — Writing masked out list values to json
- **fixed** — Deadlock in streaming distributor

##### ✨ Enhancements

- Improved expression autocomplete for `IPython`, `Jupyter`, and `Marimo` (#22221)

##### 🐞 Bug fixes

- Incorrect condition on empty inner join fast path (#22208)
- Fallback predicate filter for `min=max` with `is_in` (#22213)
- Don't panic for `LruCachedFunc` for `size=0` (#22215)
- Writing masked out list values to json (#22210)
- Deadlock in streaming distributor (#22207)

Thank you to all our contributors for making this release possible!
@Matt711, @alexander-beedie, @coastalwhite, @dependabot[bot], @orlp, @ritchie46 and [dependabot[bot]](https://github.com/apps/dependabot)