# Polars 1.7.0 — Python Polars 1.7.0

- Product: Polars (https://whatsnew.fyi/product/polars)
- Vendor: Polars
- Date: 2024-09-11
- Version: 1.7.0
- Original notes: https://github.com/pola-rs/polars/releases/tag/py-1.7.0
- Permalink: https://whatsnew.fyi/product/polars/releases/1.7.0

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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- **added** — Support IO[bytes] and bytes in scan_{...} functions
- **added** — IEJoin algorithm for non-equi joins and support for Full non-equi joins
- **added** — Optimizer rules for is_null().all() and similar expressions to use null_count()
- **added** — Tooltip by default to charts
- **added** — Support for shortcut eval of common boolean filters in SQL interface WHERE clause
- **added** — Make expressions containing Python UDFs serializable
- **changed** — Back arrow arrays with SharedStorage which can have non-refcounted static slices
- **changed** — PlSmallStr implementation from Arc<str> to compact_str
- **changed** — Enable Parquet parallel=prefiltered for auto
- **changed** — BytecodeParser for upcoming Python 3.13
- **changed** — join_where semantics
- **fixed** — Use IO[bytes] instead of BytesIO in DataFrame.write_parquet()
- **fixed** — Scalar checks
- **fixed** — Scanning hive partitioned files where hive columns are partially included in the file
- **fixed** — Use Buffer<T> in ObjectSeries, fixes variety of offset bugs
- **fixed** — Properly slice validity mask on pl.Object series
- **fixed** — Raise if single argument form in replace/replace_strict is not a mapping
- **fixed** — Group first value after group-by slice
- **fixed** — Allow for date/datetime subclasses such as pd.Timestamp and FreezeGun in pl.lit
- **fixed** — Output type for list.eval in certain cases

##### 🏆 Highlights

- Add support for `IO[bytes]` and `bytes` in `scan_{...}` functions (#18532)
- Add IEJoin algorithm for non-equi joins and support Full non-equi joins (#18365)

##### 🚀 Performance improvements

- Back arrow arrays with SharedStorage which can have non-refcounted static slices (#18666)
- Don't traverse file list twice for extension validation (#18620)
- Remove cloning of `ColumnChunkMetadata` (#18615)
- Add upfront partitioning in `ColumnChunkMetadata` (#18584)
- Enable Parquet `parallel=prefiltered` for `auto` (#18514)
- Change `PlSmallStr` impl from `Arc<str>` to `compact_str` (#18508)
- Added optimizer rules for `is_null().all()` and similar expressions to use `null_count()` (#18359)

##### ✨ Enhancements

- Update `BytecodeParser` for upcoming Python 3.13 (#18677)
- Add tooltip by default to charts (#18625)
- Add support for `IO[bytes]` and `bytes` in `scan_{...}` functions (#18532)
- Support shortcut eval of common boolean filters in SQL interface "WHERE" clause (#18571)
- Add IEJoin algorithm for non-equi joins and support Full non-equi joins (#18365)
- Make expressions containing Python UDFs serializable (#18135)

##### 🐞 Bug fixes

- Use IO[bytes] instead of BytesIO in `DataFrame.write_parquet()` (#18652)
- Scalar checks (#18627)
- Scanning hive partitioned files where hive columns are partially included in the file (#18626)
- Enable "polars-json/timezones" feature from "polars-io" (#18635)
- Use Buffer\<T> in ObjectSeries, fixes variety of offset bugs (#18637)
- Properly slice validity mask on pl.Object series (#18631)
- Raise if single argument form in `replace`/`replace_strict` is not a mapping (#18492)
- Fix group first value after group-by slice (#18603)
- Allow for date/datetime subclasses (e.g. pd.Timestamp, FreezeGun) in pl.lit (#18497)
- Fix output type for `list.eval` in certain cases (#18570)
- Fix `map_elements` for List return dtypes (#18567)
- Check for duplicate column names in `read_database` cursor result, raising `DuplicateError` if found (#18548)
- Do not remove double-sort if `maintain_order=True` (#18561)
- Empty any\_horizontal should be false, not true (#18545)
- Fix type inference error in `map_elements` for List types (#18542)
- Address incorrect `align_frames` result when the alignment column contains NULL values (#18521)
- Fix advertised version in source builds (#18523)
- Handle Parquet projection pushdown with only row index (#18520)
- DataFrame `write_database` not passing down "engine\_options" when using ADBC (#18451)
- Properly raise on invalid selector expressions (#18511)
- Wrong output column name in `or` and `xor` operations (#18512)
- Normalize by default in Series.entropy like Expr.entropy does (#18493)
- Various schema corrections (#18474)
- Don't drop objects on empty buffers (#18469)
- Expr.sign should preserve dtype (#18446)
- Ensure `assert_frame_not_equal` and `assert_series_not_equal` raise on mismatched input types (#18402)
- Fixed `Worksheet` definition in `write_excel` type annotations (#18452)

##### 📖 Documentation

- Update join\_where docs to clarify behaviour (#18670)
- Fix multiprocessing docs regarding fork method check (#18563)
- Various docstring improvements to `testing.assert_*` functions (#18494)
- Fix formula in ewm\_mean\_by (#18506)
- Pre-compute plugin\_path before defining plugin (#18503)
- Add Expr.null\_count to aggregations (#18459)

##### 🛠️ Other improvements

- Fix a bunch of tests for new-streaming (#18659)
- Don't raise on multiple same names in ie\_join (#18658)
- Check predicates in join\_where (#18648)
- Change join\_where semantics (#18640)
- Add benchmark tests for join\_where with inequalities (#18614)
- Check number of binary comparisons in join\_where predicates (#18608)
- Raise on suffixed predicate in join\_where (#18607)
- Fix Python docs build (#18605)
- Use `streaming` argument in `test_parquet_slice_pushdown_non_zero_offset` (#18529)
- Fix delta test merge (#18601)
- Alter/skip some tests for new streaming (

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