Time shift: timeshift

Syntax

timeshift ( op , shiftNumber )

Input parameters

op	the operand
shiftNumber	the number of periods to be shifted

Examples of valid syntaxes

timeshift ( DS_1, 2 )

Semantics for scalar operations

This operator does not perform scalar operations.

Input parameters type

op

dataset { identifier < time > _ , identifier _* }

shiftNumber

integer

Result type

result

dataset { identifier < time > _ , identifier _* }

Additional Constraints

The operand dataset has an Identifier of type time, date or time_period and may have other Identifiers.

Behavior

This operator takes in input a Data Set of time series and, for each time series of the Data Set, shifts the reference time Identifier of a number of periods (of the time series) equal to the shiftNumber parameter. If shiftNumber is negative, the shift is in the past, otherwise it is in the future. For example, if the period of the time series is month and shiftNumber is -1 the reference time Identifier is shifted of two months in the past.

The operator can be applied only on Data Sets of time series and returns a Data Set of time series.

The result Data Set has the same Identifier, Measure and Attribute Components as the operand Data Set and contains the same time series as the operand, because the time series Identifiers (all the Identifiers except the reference time Identifier) are not changed.

The Attribute propagation rule is not applied.

As mentioned in the section “Behaviour of the Time Operators”, the operator is assumed to know which is the time Identifier as well as the period of each data point.