# Polars 1.8.1 — Python Polars 1.8.1

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2024-09-23
- Version: 1.8.1
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.8.1
- Permalink: https://whatsnew.fyi/product/polars/releases/1.8.1

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** — Cache register plugin function
- **fixed** — Properly calculate duration units
- **fixed** — Check values in strict cast Int to Time
- **fixed** — Fix typo in DuplicateError error message
- **fixed** — Properly merge live- and dead columns in prefiltered
- **changed** — Make with_column_unchecked take Column
- **changed** — Keep scalar in more places

##### 🚀 Performance improvements

- Cache register plugin function (#18860)

##### 🐞 Bug fixes

- Properly calculate duration units (#18869)
- Check values in strict cast Int to Time (#18854)
- Fix typo in DuplicateError error message (#18855)
- Properly merge live- and dead columns in prefiltered (#18862)

##### 📖 Documentation

- Fix minor rogue apostrophes (#18865)

##### 🛠️ Other improvements

- Make `with_column_unchecked` take `Column` (#18863)
- Keep scalar in more places (#18775)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @coastalwhite, @mcrumiller, @ritchie46 and @rodrigogiraoserrao