Python Polars 0.16.2

🚀 Performance improvements

• improve dynamic groupby performance on sorted keys (#6599)

✨ Enhancements

• implement fill_null for list data (#6635)
• expression functions should be nullable (#6629)
• Implement unary plus operation on exprs and series (#6517)
• add streamable udfs (#6614)
• is_first for struct dtype (#6595)
• Added from_str_radix method to StringNameSpace that allows to parse strings from any base to i32 (#6570)
• Implement DataFrame Interchange Protocol through pyarrow (#6581)
• improve predicate pushdown (#6579)
• raise error on invalid binary cmp (#6564)

🐞 Bug fixes

• make string_repr private (#6636)
• treat literal values consistently in select context, improve related typing (#6628)
• Fix _repr_html_ double-height rows (#5645) (#6534)
• fix(rust, python) cast to and from fixed offsets (#6602)
• raise error on string numeric arithmetic (#6601)
• don't convert "ns"-precision temporal types via pyarrow (#6592)
• partially assert sortedness in groupby dynamic (#6593)
• fix(rust, python); raise oob if negative index given to take (#6590)
• fix predicate pushdown key check (#6577)
• fix schema of apply with many inputs on empty df (#6571)
• let lhs determine struct order in supertype (#6572)
• ensure consistent handling of 1D numpy arrays with respect to other sequences (#6569)
• fix(rust, python) validate utc, fmt, and tz-aware in strptime (#6550)
• add strptime to filter boundary (#6560)

🛠️ Other improvements

• make string_repr private (#6636)
• add example of using is_between with string bounds, and extend test coverage for the same (#6627)
• provide additional examples for diff methods (#6630)
• Consistent handling of env vars (#6626)
• make structify behaviour experimental, while also extending it to aliased expressions (#6615)
• Disallow clippy borrow deref ref (#6605)
• Update ruff version and some settings (#6588)
• Add release flow info to contributing guide (#6480)
• Use assert_series_equal instead of s.series_equal(...) (#6582)
• cleanup last vestiges of experimental kwargs setting (#6568)
• Use assert_frame_equal instead of assert df.frame_equal(...) (#6553)
• Update to PyO3 to 0.18.0 (#6531)

Thank you to all our contributors for making this release possible!
@2-5, @MarcoGorelli, @abalkin, @alexander-beedie, @cojmeister, @dependabot, @dependabot[bot], @jjerphan, @plaflamme, @ritchie46 and @stinodego

Python Polars 0.16.1

🏆 Highlights

• Formalize list aggregation difference between groupbys, selection and window functions (#6487)
• automagically upconvert with_columns kwarg expressions with multiple output names to struct; extend **named_kwargs support to select (#6497)

⚠️ Breaking changes

• error on string <-> date cmp (#6498)
• Formalize list aggregation difference between groupbys, selection and window functions (#6487)
• show where error messages originated (#6482)
• Remove deprecated paths from Series.__getitem__ (#6048)
• change behaviour of named rows (#6302)
• Remove deprecated read/write_json arguments (#5990)
• make schema, schema_overrides, and orient consistent on all user-facing interfaces (#6387)
• Groupby iteration now returns tuples of (name, data) (#6350)
• Remove Groupby.pivot (#6016)
• Remove deprecated argument aliases (#5993)
• Change Series.shuffle default behaviour (#5991)
• Change Expr.is_between default behaviour (#5985)
• Restrict certain function parameters to be keyword-only (#6464)

✨ Enhancements

• let cast_time_zone accept None (#6539)
• automagically upconvert with_columns kwarg expressions with multiple output names to struct; extend **named_kwargs support to select (#6497)
• add some missing type annotation in series dispatch methods (#6523)
• better errors in get_ptr and a probability on a boolean… (#6522)
• add utc parameter to strptime (#6496)
• add meta 'has_multiple_outputs', 'is_regex_projec… (#6500)
• error on string <-> date cmp (#6498)
• ~30% faster iter_rows(named=True) and to_dicts(), if pyarrow available (#6493)
• show where error messages originated (#6482)
• Remove deprecated paths from Series.__getitem__ (#6048)
• change behaviour of named rows (#6302)
• Remove deprecated read/write_json arguments (#5990)
• Groupby iteration now returns tuples of (name, data) (#6350)
• Remove Groupby.pivot (#6016)
• Remove deprecated argument aliases (#5993)
• Change Series.shuffle default behaviour (#5991)
• Change Expr.is_between default behaviour (#5985)
• Restrict certain function parameters to be keyword-only (#6464)

🐞 Bug fixes

• implement ser/de for BinaryChunked (#6543)
• on frame-init from generator, initial chunk_size cannot be smaller than infer_schema_length (#6541)
• raise if tz_localize called on UTC-aware (#6526)
• make concat_list group aware (#6527)
• error on invalid expanding expression (#6521)
• create from dicts directly as struct categorical (#6520)
• fix oob in arr.get by expressions (#6519)
• fix cse schema (#6518)
• panic when max_len -1 is reached (#6494)
• Formalize list aggregation difference between groupbys, selection and window functions (#6487)
• fix(rust, python) validate tz in with_time_zone (#6417)

🛠️ Other improvements

• Remove verify_series_and_expr_api util (#6524)
• Disable some tests for Windows (#6532)
• Remove unnecessary brackets in doc examples (#6332)
• Enable some tests for Windows (#6511)
• Fix test issue with tmp directory (#6508)
• Fix some deprecation warnings (#6495)
• added all missing examples for temporal expressions (#6488)
• Utilize pytest-xdist for faster unittests (#6483)
• test(python) I/O test improvements (#6475)
• make schema, schema_overrides, and orient consistent on all user-facing interfaces (#6387)
• improved error message from Expr on incorrect usage in boolean context (#6473)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @alexander-beedie, @gab23r, @papparapa, @ritchie46, @romanovacca, @stinodego and @zundertj

Python Polars 0.15.18

✨ Enhancements

• More precise pipe type annotation (#6457)

🐞 Bug fixes

• use consistent floor division for floats/ints (#6460)
• split semi/anti join optimization (#6459)

🛠️ Other improvements

• Specify deltalake minimum version (#6363)
• deprecate iterrows in favour of iter_rows, add new @redirect class decorator (#6461)
• Improve IO test structure (#6453)

Thank you to all our contributors for making this release possible!
@alexander-beedie, @josh, @ritchie46 and @stinodego

Python Polars 0.15.17

✨ Enhancements

• allow expr in str.contains (#6443)
• Deprecate with_column (#6128)
• expose efficient iterator over DataFrame slices (#6414)
• add float formatting option (#6432)
• 10% speedup for to_dicts method (#6415)
• add datetime/duration dtype selector groups covering the different timeunits (#6425)
• allow internal api to get pointer to values buffer (#6385)
• infer ISO8601 datetimes (#6357)
• minor improvement to auto-detection of ambiguous data orientation (#6376)
• allow expressions as arguments in str.ends_with (#6361)
• Make groupby rolling/dynamic iterable (#6372)
• accept expr in str.starts_with (#6355)
• Move explode to namespaces (#6351)
• Rename Series.struct.to_frame to .struct.unnest (#6352)
• auto-detect %+ as tz-aware (#6434)

🐞 Bug fixes

• fix projection pushdown on double semi join (#6440)
• ensure column-exclusion works with the new dtype groups, and improve some related typing (#6442)
• ensure from_dicts and DataFrame init from list of dicts behave consistently, update/improve related docstrings (#6431)
• cumulative_eval ensure output dtype is respected (#6435)
• allow from pandas null structs (#6430)
• fixed interaction of schema_overrides with frame-init from list of dicts (#6424)
• only use float simd on specific alignment (#6427)
• no early escape when window is equal to len in rolling_float (#6408)
• is_between typing with time in start and end (#6393)
• dont incorrectly infer Zulu time (#6378)
• raise error on invalid sort_by argument (#6382)
• take offset into account with str.explode (#6384)
• Return empty batch for pl.read_csv_batched().next_… (#6381)
• ensure pyarrow.compute module is loaded (#6353)
• implement ser/de for StructChunked (#6359)
• series of empty structs (#6347)

🛠️ Other improvements

• add explicit note about use of Config as a context manager (#6439)
• ensure from_dicts and DataFrame init from list of dicts behave consistently, update/improve related docstrings (#6431)
• Fix docstring of series.interpolate (#6399)
• Remove duplicate test (#6390)
• deprecate columns param for DataFrame init; transitioning to schema (#6366)
• Add docs and tests to Expr.flatten (#6370)
• Example of filtering partitioned delta tables (#6365)
• Uppercase project URL refs (#6362)

Thank you to all our contributors for making this release possible!
@ChayimFriedman2, @MarcoGorelli, @alexander-beedie, @c-peters, @flowlight0, @gab23r, @gam-phon, @ghuls, @jgmartin, @josh, @ritchie46, @romanovacca, @stinodego, @universalmind303 and @zundertj

Python Polars 0.15.16

🚀 Performance improvements

• Improve rechunk check (#6268)
• reuse allocated scratches in ipc writer (#6287)
• use dedicated writer thread for sink_parquet (#6285)

✨ Enhancements

• add strict parameter to decoding expressions (#6342)
• allow unordered struct creating from anyvalues (#6321)
• allow pass_name in aggregation apply (#6318)
• parse abbrev month name (#6314)
• Add warning for new behaviour of named rows (#6300)
• add dt.combine for combining date and time components (#6121)
• improvements to dtype-based column selection (#6295)
• add sink_ipc (#6286)
• additional schema_overrides param for more ergonomic DataFrame init (#6230)

🐞 Bug fixes

• don't cast nulls before trying normal cast (#6339)
• properly dispatch categorical string comparison (#6336)
• expand all nested wildcards in functions (#6334)
• fix groupby rolling by_key if groups are empty (#6333)
• Fix some type hints and bugs for groupby (#6329)
• Reject None input for head/tail (#6326)
• parse abbrev month name (#6314)
• default to pyarrow for writing parquet (#6313)
• disallow alias in inline join expressions (#6312)
• block proj-pd and pred-pd on swapping rename (#6303)
• convert nested dictionary with i64 keys (#6299)
• fix(python) Print instantiated dtypes in glimpse (#6298)
• infer y-m-d datetime even if single element (#6297)
• fix panic dynamic_groupby on empty dataframe (#6294)
• implement missing DataFrame __floordiv__ op (#6280)
• Allow low and high in date_range to be str (#6275)
• allow integer-compatible row indexes that are not strictly typed as int (#6266)
• Parse negative dates with polars parser (#6256)

🛠️ Other improvements

• run cse optimization only if joins and caches… (#6337)
• Fix wrong description for variable_name argument in melt (#6331)
• Fix random groupby test failure (#6327)
• fixup test names, adjust test_struct (#6317)
• simplify _from_pandas constructor (#6310)
• Ignore hash doctests (#6304)
• Fix docstring formatting for truncate (#6291)
• Move package metadata to pyproject.toml (#6271)
• Move io tests to the same folder (#6277)
• Enable Dependabot (#5036)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @alexander-beedie, @c-peters, @dependabot, @dependabot[bot], @ghuls, @n8henrie, @ritchie46, @stinodego and @universalmind303

Python Polars 0.15.15

✨ Enhancements

• ensure ooc sort works ooc with all-constant values (#6235)
• The 1 billion row sort (#6156)
• optionally treat missing UTF8 values as the empty string at CSV parse-time (#6203)
• check file target is not an existing directory (#6187)
• support -ve indexing for DataFrame head and tail methods (#6173)
• Implement DataFrame.unique(keep="none") (#6169)
• support use of explicit Struct dtypes on DataFrame/Series init (#6145)

🐞 Bug fixes

• Add list inner dtype when printing Series (#6233)
• strptime now respects pl.Datetime's time_unit (#6231)
• fix when then otherwise with arity and aggregation… (#6224)
• collect now uses the storage_options given to scan_parquet (#6223)
• set_sorted keep schema (#6222)
• pass name to value counts in aggregation (#6221)
• don't set fast_explode on list of structs (#6220)
• address a frame init/construction error, and expose infer_schema_length to frame init (#6210)
• explode of empty nullable list (#6190)
• fix oob arr.take (#6189)
• Make with_columns in with_columns_kwargs mode compatible with more data types (#6126)
• Update docstring with_columns to reflect a new dataframe is being returned (#6122)
• fix empty streaming joins (#6149)
• fix streaming joins where the join order has been … (#6143)
• write tz-aware datetimes to csv (#6135)
• add null behavior for oob indices (#6133)

🛠️ Other improvements

• Create DataFrame from schema (#6225)
• don't set aggregated flag on null propagated aggregation. (#6191)
• undo cargo.toml change (#6219)
• Improve drop_nulls docstrings (#6127)
• Clarify docstrings for closed argument (#6198)
• minor docs and typing updates (plus additional test coverage for related areas) (#6182)
• explain n_field_strategy (#6158)

Thank you to all our contributors for making this release possible!
@MarceColl, @MarcoGorelli, @alexander-beedie, @gab23r, @ghuls, @jvanbuel, @n8henrie, @rben01, @ritchie46, @ropoctl, @sorhawell, @stinodego, @winding-lines and @zundertj

Python Polars 0.15.14

🚀 Performance improvements

• first check rev-map on categorical equality check (#6085)

✨ Enhancements

• add arr.take expression (#6116)
• allow extend_constant to work with date literals (#6114)
• allow nested categorical cast (#6113)
• add a rounded_corners modifier to pl.Config.set_tbl_formatting (#6108)
• huge speedup of scalar-to-array expansion on frame init from dict (#6111)
• extend existing fast range->Series init to lists of ranges in a Series (#6099)
• additional (opt-in) options for assert_frame_equal (#6096)
• add search_sorted for arrays and utf8 dtype (#6083)

🐞 Bug fixes

• ensure multi-line type hints are parenthesised (#6100)
• fix invalid dtype in chunked array after struct cast (#6093)
• don't run cse cache_states if no projections found (#6087)
• Support all datatypes in glimpse and align with head/tail (#6091)
• Update read_csv error message (#6082)
• propogate nulls in binary arithmetic/aggregation (#6076)

🛠️ Other improvements

• Fix docstring with_context (#6118)
• Use Dataframe.item internally and in tests (#6109)
• Assert deprecation warning on check_column_names (#6110)
• enable unused import autofix via ruff (#6102)

Thank you to all our contributors for making this release possible!
@alexander-beedie, @gitkwr, @huitseeker, @ritchie46, @stinodego and @zundertj

Python Polars 0.15.13

✨ Enhancements

• Improve iterating over GroupBy (#6051)
• much faster lazy type-checks (#6064)
• support array-expansion of scalars on frame init from dict (#6034)
• improve error message when writing nested data to… (#6040)

🐞 Bug fixes

• bound complex type from 3.8 to 3.11 (#6071)
• deal with unnest schema expansion in projection pd (#6063)
• correct output dtype for cummin/cumsum/cummax (#6062)
• block streaming on literal series/range (#6058)
• improve handling of dict-type "columns" param on frame-init (#6045)
• Fix typing for DataFrame.select (#6047)
• ndjson struct inference (#6049)
• fix stringcache. latest refactor introduced a hashing error (#6056)
• allow mixed field order and availability in apply that r… (#6041)
• deal with empty structs (#6039)
• fix aggregation that filters out all data (#6036)
• fix diff overflow (#6033)
• keep column names in is_null/is_not_null (#6032)
• keep name when sorting categorical in lexial order (#6029)
• tweaked property/accessor behaviour (#6021)
• properly set null anyvalue if categorical is neste… (#6025)
• Fix from_epoch function signature (#6024)
• Validate estimated_size parameter (#6018)

🛠️ Other improvements

• suggest forward fill in cumsum/cummax (#6061)
• Fix SIM105 issues. (#6042)
• Remove trailing spaces in glimpse output (#6037)
• Remove unnecessary noqa's (#6035)
• Fix flake8-pytest-style errors in tests. (#6031)
• update read_sql and row docstrings (#6028)
• Enable the isort-style import autofix via ruff (#6020)
• Update py-polars/Cargo.lock (#6013)
• Refactor pivot tests (#6012)
• Use ruff instead of isort, flake8 and pyupgrade (#5916)
• Properly deprecate groupby.pivot (#6000)

Thank you to all our contributors for making this release possible!
@alexander-beedie, @ghuls, @ritchie46, @stinodego and @universalmind303

Python Polars 0.15.11

🚀 Performance improvements

• ensure set_at_idx is O(1) (#5977)

✨ Enhancements

• allow eq,ne,lt etc (#5995)
• Improve Expr.is_between API (#5981)
• large speedup for df.iterrows (~200-400%) (#5979)
• updated default table format from "UTF8_FULL" to "UTF8_FULL_CONDENSED" (#5967)
• Access rows as namedtuples (#5966)
• Improve assert_frame_equal messages (#5962)

🐞 Bug fixes

• make weekday tz-aware (#5989)
• fix categorical in struct anyvalue issue (#5987)
• fix invalid boolean simplification (#5976)
• allow empty sort on any dtype (#5975)
• properly deal with categoricals in streaming queries (#5974)

Thank you to all our contributors for making this release possible!
@alexander-beedie, @ritchie46 and @stinodego

Python Polars 0.15.9

🚀 Performance improvements

• improve reducing window function performance ~33% (#5878)

✨ Enhancements

• str.strip with multiple chars (#5929)
• add iterrrows (#5945)
• read decimal as f64 (#5938)
• improve query plan scan formatting (#5937)
• allow all null cast (#5933)
• allow objects in struct types (#5925)
• handle Series init from python sequence of numpy arrays (#5918)
• merge sorted dataframes (#5817)
• impl hex and base64 for binary (#5892)
• Add datatype hierarchy (#5901)
• Add .item() on DataFrame and Series (#5893)
• make get_any_value fallible (#5877)
• Add string representation for data types (#5861)
• directly push all operator result into sink, prev… (#5856)

🐞 Bug fixes

• don't panic on ignored context (#5958)
• don't allow named expression in arr.eval (#5957)
• error on invalid dtype (#5956)
• fix panic in join expressions (#5954)
• block ordered predicates before explode (#5951)
• adhere to schema in arr.eval of empty list (#5947)
• fix from_dict schema_inference=0 (#5948)
• fix arrow nested null conversion (#5946)
• allow None in arr.slice length (#5934)
• fix time to duration cast (#5932)
• error on addition with datetime/time (#5931)
• don't create categoricals in streaming (#5926)
• object filter should keep single chunk (#5913)
• csv, read escaped "" as missing (#5912)
• fix pivot of signed integers (#5909)
• don't allow duplicate columns in read_csv arg (#5908)
• fix latest oob in streaming convertion (#5902)
• adapt k to len in topk (#5888)
• fix lazy swapping rename (#5884)
• fix window function with nullable values; regression due… (#5874)
• improve equality consistency between types (#5873)
• evaluate whole branch expression to determine if r… (#5864)
• fix top_k on empty (#5865)
• fix slice in streaming (#5854)
• Fix type hint for IO *_options arguments (#5852)

🛠️ Other improvements

• Fix docs for sink_parquet (#5952)
• Fix misspelling in LazyFrame docstring (#5917)
• add bin, series.is_sorted and merge_sorted (#5914)

Thank you to all our contributors for making this release possible!
@AnatolyBuga, @alexander-beedie, @cannero, @chitralverma, @dannyvankooten, @johngunerli, @ozgrakkurt, @ritchie46, @stinodego, @winding-lines and @zundertj