Module datarush.library

Package com.pervasive.datarush.functions

Class Statistics

java.lang.Object

com.pervasive.datarush.functions.Statistics

public class Statistics
extends Object

Provides implementations of common statistical functions. These functions are for calculating aggregations within the fields of a record. To calculate aggregations over an entire data set, use Group instead.

See Also:

ScalarValuedFunction, DeriveFields

Constructor Summary

Constructors

Constructor	Description
Statistics()

Method Summary

Modifier and Type	Method	Description
static ScalarValuedFunction	avg(String... fields)	Builds an expression computing the average of the values of the specified fields.
static ScalarValuedFunction	avg(List<ScalarValuedFunction> exprs)	Builds an expression computing the average of the specified expressions.
static ScalarValuedFunction	wavg(String[] fields, double[] weights)	Builds an expression computing the weighted average of the values of the specified fields.
static ScalarValuedFunction	wavg(List<ScalarValuedFunction> exprs, double[] weights)	Builds an expression computing the weighted average of the values of the specified expressions.

Methods inherited from class java.lang.Object

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

Constructor Detail

Statistics

public Statistics()

Method Detail

avg

public static ScalarValuedFunction avg(String... fields)

Builds an expression computing the average of the values of the specified fields.

Parameters:

fields - the fields to include in the average

Returns:

a function evaluating the expression

avg

public static ScalarValuedFunction avg(List<ScalarValuedFunction> exprs)

Builds an expression computing the average of the specified expressions.

Parameters:

exprs - the expressions to include in the average

Returns:

a function evaluating the expression

wavg

public static ScalarValuedFunction wavg(String[] fields,
                                        double[] weights)

Builds an expression computing the weighted average of the values of the specified fields.

Parameters:

fields - the fields to include in the average

weights - the weights to apply to each field

Returns:

a function evaluating the expression

Throws:

com.pervasive.datarush.graphs.physical.InvalidPropertyValueException - if the number of weights does not match the number of fields

wavg

public static ScalarValuedFunction wavg(List<ScalarValuedFunction> exprs,
                                        double[] weights)

Builds an expression computing the weighted average of the values of the specified expressions.

Parameters:

exprs - the expressions to include in the average

weights - the weights to apply to each expression

Returns:

a function evaluating the expression

Throws:

com.pervasive.datarush.graphs.physical.InvalidPropertyValueException - if the number of weights does not match the number of expressions or if no expressions are supplied