Published June 30, 2026 | Version py-1.42.1
Software Open

pola-rs/polars: Python Polars 1.42.1

Authors/Creators

  • 1. Polars
  • 2. PhD Candidate, Radboud University
  • 3. Quansight
  • 4. @aertslab
  • 5. @pola-rs
  • 6. CWI
  • 7. University of California, Berkeley
  • 8. @Quantco

Description

⚠️ Deprecations

  • Deprecate strict parameter of pl.concat, replace with new how='horizontal_extend' (#27965)

🚀 Performance improvements

  • Add a sampled resolve mode for multi-file parquet metadata (#28111)
  • Speed up small dtype series sums with a upcast sum kernel (#27958)
  • Don't block on path expansion (#28073)

✨ Enhancements

  • Close ResourceWarning leaks in database tests (#28066)

🐞 Bug fixes

  • Incorrect sorted fast-path returning nan for grouped max (#28129)
  • Fix panic on scan_parquet filter of fixed-size binary column (#28122)
  • Fix decimal dynamic float cast (#28126)
  • Fix pyiceberg key dot HDFS prefix filter (#28109)
  • Fix projection pushdown panic on select(len()) after groupby (#28108)
  • Fully resolve remaining ResourceWarning leaks in database/iceberg tests (#28107)
  • Expiry time loading for AWS DeferredRefreshableCredentials (#28099)
  • Close ResourceWarning leaks in database tests (#28066)
  • Avoid panic on temporal extraction for datetime columns with nulls (#28054)
  • Prevent panic in replace when old/new contain Expr or object dtype values (#27433)

📖 Documentation

  • Fix dataset regression in the examples (#28131)
  • Emphasize to generally not ever write Rust tests (#28082)
  • Mention Polars skill in User Guide's LLM section (#28113)

🛠️ Other improvements

  • Disallow usage of tokio::spawn in clippy (#28123)
  • Improve Makefile with respect to venv robustness (#28110)
  • Remove legacy prelude glob imports from leaf files (#28114)
  • Skip pandas 3.0.4 due to pd.TimeDelta segfault (#28125)
  • Update mypy to the new 2.x release (#28116)
  • Ensure pyrefly checks run as part of make pre-commit (#28095)
  • Fix test_select_explode_height_filter_order_by failure when POLARS_MAX_THREADS=2 (#28090)
  • Add Morsel::height (#28060)

Thank you to all our contributors for making this release possible! @0guban0v, @Kevin-Patyk, @TNieuwdorp, @alexander-beedie, @azimafroozeh, @dsprenkels, @kdn36, @nameexhaustion, @orlp, @raphaelroshan, @ritchie46 and @sar-cheng

Files

pola-rs/polars-py-1.42.1.zip

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Additional details

Related works

Is supplement to
Software: https://github.com/pola-rs/polars/tree/py-1.42.1 (URL)

Software

Repository URL
https://github.com/pola-rs/polars