Struct datafusion_expr::WindowUDF

pub struct WindowUDF { /* private fields */ }

Logical representation of a user-defined window function (UDWF) A UDWF is different from a UDF in that it is stateful across batches.

See the documentation on PartitionEvaluator for more details

1. For simple use cases, use create_udwf (examples in simple_udwf.rs).

2. For advanced use cases, use WindowUDFImpl which provides full API access (examples in advanced_udwf.rs).

API Note

This is a separate struct from WindowUDFImpl to maintain backwards compatibility with the older API.

Implementations

impl WindowUDF

pub fn new( name: &str, signature: &Signature, return_type: &ReturnTypeFunction, partition_evaluator_factory: &PartitionEvaluatorFactory, ) -> Self

👎Deprecated since 34.0.0: please implement WindowUDFImpl instead

Create a new WindowUDF from low level details.

See WindowUDFImpl for a more convenient way to create a WindowUDF using trait objects

pub fn new_from_impl<F>(fun: F) -> WindowUDF

where F: WindowUDFImpl + 'static,

Create a new WindowUDF from a [WindowUDFImpl] trait object

Note this is the same as using the From impl (WindowUDF::from)

pub fn inner(&self) -> &Arc<dyn WindowUDFImpl>

Return the underlying WindowUDFImpl trait object for this function

pub fn with_aliases( self, aliases: impl IntoIterator<Item = &'static str>, ) -> Self

Adds additional names that can be used to invoke this function, in addition to name

If you implement WindowUDFImpl directly you should return aliases directly.

pub fn call(&self, args: Vec<Expr>) -> Expr

creates a Expr that calls the window function with default values for order_by, partition_by, window_frame.

See ExprFunctionExt for details on setting these values.

This utility allows using a user defined window function without requiring access to the registry, such as with the DataFrame API.

pub fn name(&self) -> &str

Returns this function’s name

See WindowUDFImpl::name for more details.

pub fn aliases(&self) -> &[String]

Returns the aliases for this function.

pub fn signature(&self) -> &Signature

Returns this function’s signature (what input types are accepted)

See WindowUDFImpl::signature for more details.

pub fn return_type(&self, args: &[DataType]) -> Result<DataType>

Return the type of the function given its input types

See WindowUDFImpl::return_type for more details.

pub fn simplify(&self) -> Option<WindowFunctionSimplification>

Do the function rewrite

See WindowUDFImpl::simplify for more details.

pub fn partition_evaluator_factory(&self) -> Result<Box<dyn PartitionEvaluator>>

Return a PartitionEvaluator for evaluating this window function

Trait Implementations

impl Clone for WindowUDF

fn clone(&self) -> WindowUDF

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WindowUDF

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for WindowUDF

Defines how the WindowUDF is shown to users

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<F> From<F> for WindowUDF

where F: WindowUDFImpl + Send + Sync + 'static,

fn from(fun: F) -> Self

Converts to this type from the input type.

impl Hash for WindowUDF

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for WindowUDF

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for WindowUDF