org.apache.druid.query.expression

Class ArrayQuantileExprMacro

java.lang.Object

org.apache.druid.query.expression.ArrayQuantileExprMacro

All Implemented Interfaces:

ExprMacroTable.ExprMacro, NamedFunction

public class ArrayQuantileExprMacro
extends Object
implements ExprMacroTable.ExprMacro

Computes a particular quantile from a numeric array. Usage: array_quantile(array, rank). The requested quantile is given by "rank", which must be from 0 to 1, inclusive: 0 is the minimum, 1 is the maximum. Null values in the input array are ignored. Returns Double.NaN if the requested quantile is below 0 or above 1. Returns Double.NaN if the input array is numeric, yet contains no nonnull elements. Returns null if the input is not a numeric array at all. If the requested quantile falls between two elements of the input array, the result is a linear interpolation of the two closest values. According to Wikipedia (https://en.wikipedia.org/wiki/Quantile), the interpolation algorithm we're using is the default method in R, NumPy, and Julia, and matches Excel's PERCENTILE.INC function.

Field Summary

Fields

Modifier and Type	Field and Description
static String	FN_NAME

Constructor Summary

Constructors

Constructor and Description
ArrayQuantileExprMacro()

Method Summary

Modifier and Type	Method and Description
Expr	apply(List<Expr> args)
String	name() Name of the function

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.druid.math.expr.NamedFunction

processingFailed, validationFailed, validationFailed, validationHelperCheckAnyOfArgumentCount, validationHelperCheckArgIsLiteral, validationHelperCheckArgumentCount, validationHelperCheckArgumentCount, validationHelperCheckArgumentRange, validationHelperCheckLambaArgumentCount, validationHelperCheckMinArgumentCount, validationHelperCheckMinArgumentCount

Field Detail

FN_NAME

public static final String FN_NAME

See Also:

Constant Field Values

Constructor Detail

ArrayQuantileExprMacro

public ArrayQuantileExprMacro()

Method Detail

name

public String name()

Description copied from interface: NamedFunction

Name of the function

Specified by:

name in interface NamedFunction

apply

public Expr apply(List<Expr> args)

Specified by:

apply in interface ExprMacroTable.ExprMacro