Struct datafusion::functions::string::levenshtein::LevenshteinFunc

pub struct LevenshteinFunc { /* private fields */ }

Implementations

impl LevenshteinFunc

pub fn new() -> LevenshteinFunc

Trait Implementations

impl Debug for LevenshteinFunc

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

Formats the value using the given formatter.

impl Default for LevenshteinFunc

fn default() -> LevenshteinFunc

Returns the “default value” for a type.

impl ScalarUDFImpl for LevenshteinFunc

fn as_any(&self) -> &(dyn Any + 'static)

Returns this object as an Any trait object

fn name(&self) -> &str

Returns this function’s name

fn signature(&self) -> &Signature

Returns the function’s Signature for information about what input types are accepted and the function’s Volatility.

fn return_type( &self, arg_types: &[DataType], ) -> Result<DataType, DataFusionError>

What DataType will be returned by this function, given the types of the arguments.

fn invoke( &self, args: &[ColumnarValue], ) -> Result<ColumnarValue, DataFusionError>

Invoke the function on args, returning the appropriate result

fn display_name(&self, args: &[Expr]) -> Result<String, DataFusionError>

Returns the user-defined display name of the UDF given the arguments

fn return_type_from_exprs( &self, _args: &[Expr], _schema: &dyn ExprSchema, arg_types: &[DataType], ) -> Result<DataType, DataFusionError>

What DataType will be returned by this function, given the arguments?

fn invoke_no_args( &self, _number_rows: usize, ) -> Result<ColumnarValue, DataFusionError>

Invoke the function without args, instead the number of rows are provided, returning the appropriate result.

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

Returns any aliases (alternate names) for this function.

fn simplify( &self, args: Vec<Expr>, _info: &dyn SimplifyInfo, ) -> Result<ExprSimplifyResult, DataFusionError>

Optionally apply per-UDF simplification / rewrite rules.

fn short_circuits(&self) -> bool

Returns true if some of this exprs subexpressions may not be evaluated and thus any side effects (like divide by zero) may not be encountered Setting this to true prevents certain optimizations such as common subexpression elimination

fn evaluate_bounds( &self, _input: &[&Interval], ) -> Result<Interval, DataFusionError>

Computes the output interval for a ScalarUDFImpl, given the input intervals.

fn propagate_constraints( &self, _interval: &Interval, _inputs: &[&Interval], ) -> Result<Option<Vec<Interval>>, DataFusionError>

Updates bounds for child expressions, given a known interval for this function. This is used to propagate constraints down through an expression tree.

fn output_ordering( &self, _inputs: &[ExprProperties], ) -> Result<SortProperties, DataFusionError>

Calculates the SortProperties of this function based on its children’s properties.

fn coerce_types( &self, _arg_types: &[DataType], ) -> Result<Vec<DataType>, DataFusionError>

Coerce arguments of a function call to types that the function can evaluate.