polars library
Direct native-handle access to Polars expressions, plans, frames, Series, selectors, SQL, jobs, streaming, and Arrow interchange.
Create an installed-package runtime with Polars.native. During source development, Polars.open loads an explicitly built native library.
Classes
- ArrayType
-
The Polars
Arraytype: fixed-width lists of inner values. - ArrowArray
- ArrowArrayBuilder
- ArrowBinaryType
- ArrowBinaryValue
- ArrowBooleanType
- ArrowBooleanValue
- ArrowCData
- Owns heap-allocated Arrow C Data structs and their release callbacks. close and the native finalizers release each live callback exactly once.
- ArrowCStream
- Owns a heap-allocated Arrow C Stream and its release callback.
- ArrowDataType
- ArrowDateType
- ArrowDecimalType
- ArrowDecimalValue
- ArrowDictionaryIndexValue
- ArrowDictionaryType
- ArrowDurationType
- ArrowExtensionType
- ArrowExtensionValue
- ArrowField
- ArrowFixedSizeBinaryType
- Fixed-width binary: every value has exactly byteWidth bytes.
- ArrowFixedSizeListType
- ArrowFloatingType
- ArrowFloatingValue
- An IEEE floating-point bit pattern. This preserves NaN payloads and signed zero.
- ArrowIntegerType
- ArrowIntegerValue
- ArrowIntervalType
- Calendar interval in the given unit.
- ArrowIntervalValue
- An Arrow interval. Only the components relevant to unit are non-zero: yearMonth uses months; dayTime uses days and milliseconds; monthDayNano uses months, days, and nanoseconds.
- ArrowIpcFileReader
-
Reads an Arrow IPC random-access file (
ARROW1magic plus footer). - ArrowIpcFileWriter
- Writes an Arrow IPC random-access file.
- ArrowIpcLimits
- Resource limits applied while decoding untrusted IPC input.
- ArrowIpcStreamReader
- Reads an Arrow IPC stream (a sequence of encapsulated messages).
- ArrowIpcStreamWriter
- Writes an Arrow IPC stream terminated by the end-of-stream marker.
- ArrowListType
- ArrowListValue
- ArrowMapEntry
- One key/value pair of an ArrowMapValue. Keys are never null.
- ArrowMapType
-
Arrow
Map: a list of non-nullentriesstructs of<key, value>. - ArrowMapValue
- An Arrow map row. Entry order is preserved and duplicate keys are retained, matching the physical list-of-entries layout.
- ArrowNullType
- ArrowRunEndEncodedType
- Run-end encoded data. runEndsField must be a non-nullable int16, int32, or int64 field. Arrays of this type hold logical per-row values.
- ArrowSchema
- ArrowStringValue
- ArrowStructEntry
- ArrowStructType
- ArrowStructValue
- Ordered struct members. Names are retained to detect field-order mistakes.
- ArrowTable
- An immutable schema plus its record batches.
- ArrowTemporalValue
- A raw date/time/timestamp/duration counter in the datatype's declared unit.
- ArrowTimestampType
- ArrowTimeType
- ArrowUnionType
- Arrow sparse or dense union. Each child has a type id (default its index).
- ArrowUnionValue
- A union row tagged with its child typeId. A null value is a null in the selected child (unions have no top-level validity bitmap).
- ArrowUtf8Type
- ArrowValue
- AsOfJoinOptions
- BatchStream
- Owns a bounded native batch stream handle.
- BatchStreamPoll
- One non-blocking pull result. frame is present exactly in BatchStreamState.batch.
- BinaryOffsetType
-
The Polars
BinaryOffsettype: offset-based binary storage. - BinaryType
-
The Polars
Binarytype: arbitrary byte sequences. - BooleanType
-
The Polars
Booleantype. - CancellableQuery
- CArrowArray
- ABI-exact Arrow C Data Interface array structure.
- CArrowArrayStream
- ABI-exact Arrow C Stream Interface structure.
- CArrowSchema
- ABI-exact Arrow C Data Interface schema structure.
- CategoricalType
-
The Polars
Categoricaltype. Descriptor-only. - CsvWriteOptions
- DataFrame
- DateTimeType
-
The Polars
Datetimetype: a timestamp at a given unit. - DateType
-
The Polars
Datetype: calendar dates without a time of day. - DecimalType
-
The Polars
Decimaltype: fixed-point numbers. - DType
- A Polars data type descriptor.
- DTypeCapabilities
- The set of DTypeCapability levels supported for a data type.
- DTypeSelector
- A composable predicate over Polars datatypes.
- DurationType
-
The Polars
Durationtype: an elapsed time at a given unit. - DynamicGroupByOptions
- EnumType
-
The Polars
Enumtype: a fixed, ordered set of string categories. - EwmOptions
- ExecutionOptions
- Expr
- ExprArrayNameSpace
- ExprBinaryNameSpace
- ExprCategoricalNameSpace
- ExprDateTimeNameSpace
- ExprListNameSpace
- ExprMetaNameSpace
- ExprNameNameSpace
- ExprStringNameSpace
- ExprStructNameSpace
- ExtensionType
- A Polars extension type layered over a storage type. Descriptor-only.
- Field
- A named, typed member of a StructType.
- Float16Type
-
The Polars
Float16type: IEEE 754 half-precision floats. - Float32Type
-
The Polars
Float32type: IEEE 754 single-precision floats. - Float64Type
-
The Polars
Float64type: IEEE 754 double-precision floats. - Int128Type
-
The Polars
Int128type: signed 128-bit integers. - Int16Type
-
The Polars
Int16type: signed 16-bit integers. - Int32Type
-
The Polars
Int32type: signed 32-bit integers. - Int64Type
-
The Polars
Int64type: signed 64-bit integers. - Int8Type
-
The Polars
Int8type: signed 8-bit integers. - IpcScanOptions
- IpcStreamReadOptions
- IpcStreamWriteOptions
- IpcWriteOptions
- JobStatus
- JoinOptions
- Typed ordinary join options.
- JoinWhereOptions
- JsonReadOptions
- LazyDynamicGroupBy
- LazyFrame
- LazyGroupBy
- LazyRollingGroupBy
- LazySinkOptions
- ListType
-
The Polars
Listtype: variable-length lists of inner values. - NativeAssetProtocolClient
- A protocol client resolved through the package's bundled native code asset.
- NativeHelloCapabilities
-
An immutable view of the native
hellocapability payload. No support is inferred from Dart descriptor classes: absent native fields remain absent. - NativeProtocolClient
-
Protocol client backed by the stable
df_abi_version,df_invoke,df_buffer_free,df_handle_release,df_handle_token_new, anddf_handle_token_releaseC ABI symbols. - NdjsonScanOptions
- NullType
-
The Polars
Nulltype, whose values are all null. - ObjectType
-
The Polars
Objecttype for opaque values. Descriptor-only. - OptimizerOptions
- Overrides selected Polars 0.55.2 optimizer flags.
- OwnedBatchJsonCodec
- JSON codec for the protocol's copied, binding-owned logical column batches.
- ParquetStatisticsOptions
- ParquetWriteOptions
- Polars
- An explicit native Polars runtime. Every resource created through this object belongs exclusively to this runtime, even when two runtimes were constructed from the same ProtocolClient.
- PolarsDuration
-
A Polars duration string such as
15m,2h30m,1d, or10i. - ProfileResult
- The materialized query result and Polars node timings (microseconds).
- ProtocolClient
- ProtocolInvoker
- Injectable transport. Test transports can implement this without loading FFI.
- RecordBatch
- RecordBatchCodec
- Copied-column conversion between Arrow's owned batches and the native JSON batch representation.
- RollingGroupByOptions
- RollingOptions
- RuntimeDiagnostics
- A read-only snapshot of the native runtime's owned handle registry.
- Scalar
- An immutable, explicitly typed protocol literal.
- Selector
- A schema-dependent column selector.
- SelectorFactory
- Runtime-bound constructors for selectors and datatype selectors.
- Series
- An immutable, independently owned native Polars Series.
- SqlContext
- A mutable native Polars SQL catalog.
- StringParseOptions
- StringType
-
The Polars
Stringtype: UTF-8 text. - StructType
-
The Polars
Structtype: a record of named fields. Descriptor-only. - Then
- TimeType
-
The Polars
Timetype: a time of day without a date. - UInt128Type
-
The Polars
UInt128type: unsigned 128-bit integers. - UInt16Type
-
The Polars
UInt16type: unsigned 16-bit integers. - UInt32Type
-
The Polars
UInt32type: unsigned 32-bit integers. - UInt64Type
-
The Polars
UInt64type: unsigned 64-bit integers. - UInt8Type
-
The Polars
UInt8type: unsigned 8-bit integers. - UnknownType
- A placeholder type that Polars has not yet resolved. Descriptor-only.
- When
- WindowOptions
- WindowOrderOptions
Enums
- ArrowDateUnit
- ArrowIntervalUnit
-
Arrow interval unit, as in
IntervalUnitfrom Schema.fbs. - ArrowOffsetWidth
- Physical layout family for variable-length string, binary, and list data.
- ArrowTimeUnit
- ArrowUnionMode
- Arrow union physical layout.
- AsOfStrategy
- BatchStreamState
- CategoricalPhysical
- The physical integer width used to store categorical codes.
- ClosedWindow
- CsvQuoteStyle
- DiffNullBehavior
- DTypeCapability
- A level of support that the binding offers for a DType.
- DynamicGroupLabel
- DynamicGroupStartBy
- ExecutionEngine
- Polars 0.55.2 execution engines.
- ExplainFormat
- InterpolationMethod
- IpcCompression
- JobState
- JoinMaintainOrder
- JoinMode
- JoinValidation
- ParquetCompression
- RankMethod
- RoundMode
- TimeUnit
- The resolution of temporal types such as DateTimeType.
- TimeZoneSelectorMode
- The time-zone set used by a datetime datatype selector.
- UnknownKind
- The flavour of a not-yet-resolved UnknownType.
- WindowMapping
Extensions
Constants
- protocolVersion → const int
-
simpleDTypes
→ const List<
DType> - The 20 parameterless data types, from NullType through TimeType.
Properties
-
allDTypes
→ List<
DType> -
One representative for each of the 31 descriptors advertised by protocol
v2. Parameterized representatives are illustrative; inspect
DType.capabilities before attempting copied import/export or literals.
final
Functions
-
expandRunEnds(
ArrowRunEndEncodedType type, List< int> runEnds, List<ArrowValue?> runValues, {int? maxLength}) → List<ArrowValue?> - Expands a run-end encoding to logical rows, validating run ends.
-
nestedDictionaryTypes(
ArrowDataType type) → List< ArrowDictionaryType> -
The dictionary types strictly inside
type, in ArrowArray.nestedDictionaries order. -
validateArrowValue(
ArrowDataType type, ArrowValue value, {String path = 'value'}) → void
Typedefs
Exceptions / Errors
- ComputeException
- Polars failed while executing a query or computation.
- InternalPolarsException
- An unexpected internal failure, or an unrecognized native error category.
- InvalidRequestException
- The native runtime rejected a request as malformed or invalid.
- PolarsException
- Base class for failures reported by the native Polars runtime.
- PolarsIoException
- Reading or writing a file or stream failed in the native runtime.
- ProtocolMismatchException
- The Dart package and native library disagree on the wire protocol.
- QueryCancelledException
- A running query was cancelled before it produced a result.
- StaleHandleException
- A native handle was used after it was closed or was otherwise invalid.
- UnsupportedPolarsException
- The requested operation or data type is not supported by this binding.