v0.18.0

Breaking Changes 🚨

• Default groupby to sort=False (#7180) @isVoid
• Add libcudf API for parsing of ORC statistics (#7136) @vuule
• Replace ORC writer api with class (#7099) @rgsl888prabhu
• Pack/unpack functionality to convert tables to and from a serialized format. (#7096) @nvdbaranec
• Replace parquet writer api with class (#7058) @rgsl888prabhu
• Add days check to cudf::is_timestamp using cuda::std::chrono classes (#7028) @davidwendt
• Fix default parameter values of write_csv and write_parquet (#6967) @vuule
• Align Series.groupby API to match Pandas (#6964) @kkraus14
• Share factorize implementation with Index and cudf module (#6885) @brandon-b-miller

Bug Fixes 🐛

• Remove incorrect std::move call on return variable (#7319) @davidwendt
• Fix failing CI ORC test (#7313) @vuule
• Disallow constructing frames from a ColumnAccessor (#7298) @shwina
• fix java cuFile tests (#7296) @rongou
• Fix style issues related to NumPy (#7279) @shwina
• Fix bug when iloc slice terminates at before-the-zero position (#7277) @isVoid
• Fix copying dtype metadata after calling libcudf functions (#7271) @shwina
• Move lists utility function definition out of header (#7266) @mythrocks
• Throw if bool column would cause incorrect result when writing to ORC (#7261) @vuule
• Use uvector in replace_nulls; Fix sort_helper::grouped_value doc (#7256) @isVoid
• Remove floating point types from cudf::sort fast-path (#7250) @davidwendt
• Disallow picking output columns from nested columns. (#7248) @devavret
• Fix loc for Series with a MultiIndex (#7243) @shwina
• Fix Arrow column test leaks (#7241) @tgravescs
• Fix test column vector leak (#7238) @kuhushukla
• Fix some bugs in java scalar support for decimal (#7237) @revans2
• Improve assert_eq handling of scalar (#7220) @isVoid
• Fix missing null_count() comparison in test framework and related failures (#7219) @nvdbaranec
• Remove floating point types from radix sort fast-path (#7215) @davidwendt
• Fixing parquet benchmarks (#7214) @rgsl888prabhu
• Handle various parameter combinations in replace API (#7207) @galipremsagar
• Export mock aws credentials for s3 tests (#7176) @ayushdg
• Add MultiIndex.rename API (#7172) @isVoid
• Fix importing list & struct types in from_arrow (#7162) @galipremsagar
• Fixing parquet precision writing failing if scale is equal to precision (#7146) @hyperbolic2346
• Update s3 tests to use moto_server (#7144) @ayushdg
• Fix JIT cache multi-process test flakiness in slow drives (#7142) @devavret
• Fix compilation errors in libcudf (#7138) @galipremsagar
• Fix compilation failure caused by -Wall addition. (#7134) @codereport
• Add informative error message for sep in CSV writer (#7095) @galipremsagar
• Add JIT cache per compute capability (#7090) @devavret
• Implement __hash__ method for ListDtype (#7081) @galipremsagar
• Only upload packages that were built (#7077) @raydouglass
• Fix comparisons between Series and cudf.NA (#7072) @brandon-b-miller
• Handle nan values correctly in Series.one_hot_encoding (#7059) @galipremsagar
• Add unstack() support for non-multiindexed dataframes (#7054) @isVoid
• Fix read_orc for decimal type (#7034) @rgsl888prabhu
• Fix backward compatibility of loading a 0.16 pkl file (#7033) @galipremsagar
• Decimal casts in JNI became a NOOP (#7032) @revans2
• Restore usual instance/subclass checking to cudf.DateOffset (#7029) @shwina
• Add days check to cudf::is_timestamp using cuda::std::chrono classes (#7028) @davidwendt
• Fix to_csv delimiter handling of timestamp format (#7023) @davidwendt
• Pin librdkakfa to gcc 7 compatible version (#7021) @raydouglass
• Fix fillna & dropna to also consider np.nan as a missing value (#7019) @galipremsagar
• Fix round operator's HALF_EVEN computation for negative integers (#7014) @nartal1
• Skip Thrust sort patch if already applied (#7009) @harrism
• Fix cudf::hash_partition for decimal32 and decimal64 (#7006) @codereport
• Fix Thrust unroll patch command (#7002) @harrism
• Fix loc behaviour when key of incorrect type is used (#6993) @shwina
• Fix int to datetime conversion in csv_read (#6991) @kaatish
• fix excluding cufile tests by default (#6988) @rongou
• Fix java cufile tests when cufile is not installed (#6987) @revans2
• Make cudf::round for fixed_point when scale = -decimal_places a no-op (#6975) @codereport
• Fix type comparison for java (#6970) @revans2
• Fix default parameter values of write_csv and write_parquet (#6967) @vuule
• Align Series.groupby API to match Pandas (#6964) @kkraus14
• Fix timestamp parsing in ORC reader for timezones without transitions (#6959) @vuule
• Fix typo in numerical.py (#6957) @rgsl888prabhu
• fixed_point_value double-shifts in fixed_point construction (#6950) @codereport
• fix libcu++ include path for jni (#6948) @rongou
• Fix groupby agg/apply behaviour when no key columns are provided (#6945) @shwina
• Avoid inserting null elements into join hash table when nulls are treated as unequal (#6943) @hyperbolic2346
• Fix cudf::merge gtest for dictionary columns (#6942) @davidwendt
• Pass numeric scalars of the same dtype through numeric binops (#6938) @brandon-b-miller
• Fix N/A detection for empty fields in CSV reader (#6922) @vuule
• Fix rmm_mode=managed parameter for gtests (#6912) @davidwendt
• Fix nullmask offset handling in parquet and orc writer (#6889) @kaatish
• Correct the sampling range when sampling with replacement (#6884) @ChrisJar
• Handle nested string columns with no children in contiguous_split. (#6864) @nvdbaranec
• Fix columns & index handling in dataframe constructor (#6838) @galipremsagar

Documentation 📖

• Update readme (#7318) @shwina
• Fix typo in cudf.core.column.string.extract docs (#7253) @adelevie
• Update doxyfile project number (#7161) @davidwendt
• Update 10 minutes to cuDF and CuPy with new APIs (#7158) @ChrisJar
• Cross link RMM & libcudf Doxygen docs (#7149) @ajschmidt8
• Add documentation for support dtypes in all IO formats (#7139) @galipremsagar
• Add groupby docs (#7100) @shwina
• Update cudf python docstrings with new null representation (<NA>) (#7050) @galipremsagar
• Make Doxygen comments formatting consistent (#7041) @vuule
• Add docs for working with missing data (#7010) @galipremsagar
• Remove warning in from_dlpack and to_dlpack methods (#7001) @miguelusque
• libcudf Developer Guide (#6977) @harrism
• Add JNI wrapper for the cuFile API (GDS) (#6940) @rongou

New Features 🚀

• Support numeric_only field for rank() (#7213) @isVoid
• Add support for cudf::binary_operation TRUE_DIV for decimal32 and decimal64 (#7198) @codereport
• Implement COLLECT rolling window aggregation (#7189) @mythrocks
• Add support for array-like inputs in cudf.get_dummies (#7181) @galipremsagar
• Default groupby to sort=False (#7180) @isVoid
• Add libcudf lists column count_elements API (#7173) @davidwendt
• Implement cudf::group_by (sort) for decimal32 and decimal64 (#7169) @codereport
• Add encoding and compression argument to CSV writer (#7168) @VibhuJawa
• cudf::rolling_window SUM support for decimal32 and decimal64 (#7147) @codereport
• Adding support for explode to cuDF (#7140) @hyperbolic2346
• Add libcudf API for parsing of ORC statistics (#7136) @vuule
• update GDS/cuFile location for 0.9 release (#7131) @rongou
• Add Segmented sort (#7122) @karthikeyann
• Add cudf::binary_operation NULL_MIN, NULL_MAX & NULL_EQUALS for decimal32 and decimal64 (#7119) @codereport
• Add scale and value methods to fixed_point (#7109) @codereport
• Replace ORC writer api with class (#7099) @rgsl888prabhu
• Pack/unpack functionality to convert tables to and from a serialized format. (#7096) @nvdbaranec
• Improve digitize API (#7071) @isVoid
• Add List types support in data generator (#7064) @galipremsagar
• cudf::scan support for decimal32 and decimal64 (#7063) @codereport
• cudf::rolling ROW_NUMBER support for decimal32 and decimal64 (#7061) @codereport
• Replace parquet writer api with class (#7058) @rgsl888prabhu
• Support contains() on lists of primitives (#7039) @mythrocks
• Implement cudf::rolling for decimal32 and decimal64 (#7037) @codereport
• Add ffill and bfill to string columns (#7036) @isVoid
• Enable round in cudf for DataFrame and Series (#7022) @ChrisJar
• Extend replace_nulls_policy to string and dictionary type (#7004) @isVoid
• Add segmented_gather(list_column, gather_list) (#7003) @karthikeyann
• Add method field to fillna for fixed width columns (#6998) @isVoid
• Manual merge of branch 0.17 into branch 0.18 (#6995) @shwina
• Implement cudf::reduce for decimal32 and decimal64 (part 2) (#6980) @codereport
• Add Ufunc alias look up for appropriate numpy ufunc dispatching (#6973) @VibhuJawa
• Add pytest-xdist to dev environment.yml (#6958) @galipremsagar
• Add Index.set_names api (#6929) @galipremsagar
• Add replace_null API with replace_policy parameter, fixed_width column support (#6907) @isVoid
• Share factorize implementation with Index and cudf module (#6885) @brandon-b-miller
• Implement update() function (#6883) @skirui-source
• Add groupby idxmin, idxmax aggregation (#6856) @karthikeyann
• Implement cudf::reduce for decimal32 and decimal64 (part 1) (#6814) @codereport
• Implement cudf.DateOffset for months (#6775) @brandon-b-miller
• Add Python DecimalColumn (#6715) @shwina
• Add dictionary support to libcudf groupby functions (#6585) @davidwendt

Improvements 🛠️

• Update stale GHA with exemptions & new labels (#7395) @mike-wendt
• Add GHA to mark issues/prs as stale/rotten (#7388) @Ethyling
• Unpin from numpy < 1.20 (#7335) @shwina
• Prepare Changelog for Automation (#7309) @galipremsagar
• Prepare Changelog for Automation (#7272) @ajschmidt8
• Add JNI support for converting Arrow buffers to CUDF ColumnVectors (#7222) @tgravescs
• Add coverage for skiprows and num_rows in parquet reader fuzz testing (#7216) @galipremsagar
• Define and implement more behavior for merging on categorical variables (#7209) @brandon-b-miller
• Add CudfSeriesGroupBy to optimize dask_cudf groupby-mean (#7194) @rjzamora
• Add dictionary column support to rolling_window (#7186) @davidwendt
• Modify the semantics of end pointers in cuIO to match standard library (#7179) @vuule
• Adding unit tests for fixed_point with extremely large scales (#7178) @codereport
• Fast path single column sort (#7167) @davidwendt
• Fix -Werror=sign-compare errors in device code (#7164) @trxcllnt
• Refactor cudf::string_view host and device code (#7159) @davidwendt
• Enable logic for GPU auto-detection in cudfjni (#7155) @gerashegalov
• Java bindings for Fixed-point type support for Parquet (#7153) @razajafri
• Add Java interface for the new API 'explode' (#7151) @firestarman
• Replace offsets with iterators in cuIO utilities and CSV parser (#7150) @vuule
• Add gbenchmarks for reduction aggregations any() and all() (#7129) @davidwendt
• Update JNI for contiguous_split packed results (#7127) @jlowe
• Add JNI and Java bindings for list_contains (#7125) @kuhushukla
• Add Java unit tests for window aggregate 'collect' (#7121) @firestarman
• verify window operations on decimal with java tests (#7120) @sperlingxx
• Adds in JNI support for creating an list column from existing columns (#7112) @revans2
• Build libcudf with -Wall (#7105) @trxcllnt
• Add column_device_view pointers to EncColumnDesc (#7097) @kaatish
• Add pyorc to dev environment (#7085) @galipremsagar
• JNI support for creating struct column from existing columns and fixed bug in struct with no children (#7084) @revans2
• Fastpath single strings column in cudf::sort (#7075) @davidwendt
• Upgrade nvcomp to 1.2.1 (#7069) @rongou
• Refactor ORC ProtobufReader to make it more extendable (#7055) @vuule
• Add Java tests for decimal casts (#7051) @sperlingxx
• Auto-label PRs based on their content (#7044) @jolorunyomi
• Create sort gbenchmark for strings column (#7040) @davidwendt
• Refactor io memory fetches to use hostdevice_vector methods (#7035) @ChrisJar
• Spark Murmur3 hash functionality (#7024) @rwlee
• Fix libcudf strings logic where size_type is used to access INT32 column data (#7020) @davidwendt
• Adding decimal writing support to parquet (#7017) @hyperbolic2346
• Add compression="infer" as default for dask_cudf.read_csv (#7013) @rjzamora
• Correct ORC docstring; other minor cuIO improvements (#7012) @vuule
• Reduce number of hostdevice_vector allocations in parquet reader (#7005) @devavret
• Check output size overflow on strings gather (#6997) @davidwendt
• Improve representation of MultiIndex (#6992) @galipremsagar
• Disable some pragma unroll statements in thrust sort.h (#6982) @davidwendt
• Minor cudf::round internal refactoring (#6976) @codereport
• Add Java bindings for URL conversion (#6972) @jlowe
• Enable strict_decimal_types in parquet reading (#6969) @sperlingxx
• Add in basic support to JNI for logical_cast (#6954) @revans2
• Remove duplicate file array_tests.cpp (#6953) @karthikeyann
• Add null mask fixed_point_column_wrapper constructors (#6951) @codereport
• Update Java bindings version to 0.18-SNAPSHOT (#6949) @jlowe
• Use simplified rmm::exec_policy (#6939) @harrism
• Add null count test for apply_boolean_mask (#6903) @harrism
• Implement DataFrame.quantile for datetime and timedelta data types (#6902) @ChrisJar
• Remove **kwargs from string/categorical methods (#6750) @shwina
• Refactor rolling.cu to reduce compile time (#6512) @mythrocks
• Add static type checking via Mypy (#6381) @shwina
• Update to official libcu++ on Github (#6275) @trxcllnt