Struct datafusion_expr::ScalarUDF

pub struct ScalarUDF { /* private fields */ }

Logical representation of a Scalar User Defined Function.

A scalar function produces a single row output for each row of input.

This struct contains the information DataFusion needs to plan and invoke functions such name, type signature, return type, and actual implementation.

Implementations

impl ScalarUDF

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

Create a new ScalarUDF

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

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

creates a logical expression with a call of the UDF This utility allows using the UDF without requiring access to the registry.

pub fn name(&self) -> &str

Returns this function’s name

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

Returns the aliases for this function. See ScalarUDF::with_aliases for more details

pub fn signature(&self) -> &Signature

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

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

Return the type of the function given its input types

pub fn fun(&self) -> ScalarFunctionImplementation

Return the actual implementation

Trait Implementations

impl Clone for ScalarUDF

fn clone(&self) -> ScalarUDF

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ScalarUDF

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

Formats the value using the given formatter.

impl Hash for ScalarUDF

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 ScalarUDF

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for ScalarUDF