Simple use case (addition): Offset for loop index

In the context of a For each loop, a Show alert event action is executed for each loop pass, which informs the currently processed list value via a 'Message' and names the iteration index in the 'Title', starting at 1. The $index variable provides information about the latter during iteration, although it works with a starting value of 0. This is something machines like. People tend not to. The desired result must therefore be 'converted'. The very simple formula for this is: $input + 1. This task is a clear case for the Simple calculation (+,-,*,/,%) resolver.

Configuration:

Simple use case (subtraction): 'Countdown' – iteration index in reverse gear

As in the previous example, a list of entities provided by the variable listOfEntities is processed in a loop.

Unlike the previous case, the Title of the notification issued for each iteration step should no longer display the sequence number of the iteration step (ascending from the value 1), but a 'countdown', i.e. an indication of the number of remaining iterations, which indicates the value 0 in the last step.

Configuration:

The 'countdown' can be achieved within the For each loop by forming the difference between two automatically provided 'loop variables' for each iteration step:

• $length → Integer value for the total number of iteration steps

• $index → Integer value for the current iteration index (ascending from the value 0)

In order for the countdown to display the value 0 in the last iteration, the fixed value 1 must be subtracted from the $length value in addition to the $index.

The total calculation to be performed for each iteration step is therefore: $length - $index - 1

►NOTE◄ Although the 'Countdown' count in the Title runs backwards due to the conversion, the entries in the listOfEntities are processed forwards unchanged. Reversing the direction for the iteration requires a little more effort, as the For each loop event action only iterates forwards. If the countdown index is calculated using the Simple calculation (+,-,*,/,%) resolver and stored in a variable, the name of this variable can be addressed in the 'Offset' parameter of a list item value resolver in order to retrieve the List item matching the displayed index.

More complex use case (subtraction and division): Calculating the 'age' of a company account

As an example of the possibility of creating an aggregate with different calculation operations from several instances of the Simple calculation (+,-,*,/,%) value resolver, the 'age' of a specific company account in years is determined here.

• The 'age' of an entity is considered to be the time span between the creation date (created property) and the current system time (Relative date with time with the 'Now' type).

• As time spans are always primarily determined as a millisecond difference, they must then be converted into the target unit (here: years) by division (by 'milliseconds per year').

• We calculate the duration of a year in milliseconds as 1000 ms/s x 3600 s/h x 24 h/d x 365.25 d/y = 31557600000 ms. Switching days are therefore 'apportioned' at a flat rate of 0.25 days per year.

Configuration:

►NOTE◄ Below is a configuration with the Calculate value resolver with the same content for comparison:

More complex use case (multiplication): Calculate product of efficiencies

A list with a limited number of Double values from the value range [0,1] is provided in an efficiencyFactors variable, which are to be multiplicatively concatenated as efficiencies in order to determine an overall efficiency.

Specific numerical example:

• Specifically, the value of the efficiencyFactors variable in JSON format could look like this: [0.9, 0.95, 0.75]

• This results in an overall efficiency of (0.9 x 0.95 x 0.75 = 0.64125).

Configuration:

In a Calculation expression, the list value from the variable could be processed directly in the product (Multiplication) function. Accordingly, $product($var(efficiencyFactors)) would be a target-oriented calculation expression.

As the Simple calculation (+,-,*,/,%) value resolver – as briefly mentioned in the footnote above – cannot process list values directly, the direct translation of the calculation expression into a corresponding value configuration fails.

The following approach demonstrates what a 'multiplicative concatenation' could look like for up to five factors:

►NOTE◄ The approach described above only fulfills the task if the maximum number of factors can be sufficiently limited in advance. A predetermined number of factors, on the other hand, cannot be processed. It makes little sense to cover a large number of list values in this way if they are only rarely required. The following alternative avoids this restriction.

Alternative Konfiguration:

►ANMERKUNG◄ Der Zugriff auf die Variable efficiencyFactors könnte hier auch direkt anstelle des Object property-Wertauflösers innerhalb der Berechnung erfolgen. Die Variante im Screenshot soll aber verdeutlichen, dass eine Liste von Eingangsdaten für die Berechnung als Eingabewert per Verkettung bereitgestellt werden kann. Bei Bedarf kann dann innerhalb der Berechnung auch ein Collect values-Wertauflöser verwendet werden, z. B. um Eingangsdaten aus einer Liste von komplexen Objekten zu extrahieren.

Komplexerer Anwendungsfall (Addition & Modulo): Container-Beladung

Eine Variable shipments stellt eine Liste mit Daten zu Sendungen bereit, die unter anderem das Gewicht jeder Sendung im Feld item_kgs angibt.

Deise Sendungen sollen für einen gemeinsamen Transport auf typgleiche Container verladen werden, deren maximale Zuladung eine weitere Variable kgs_per_container spezifiziert.

Unter der Annahme, dass die Stückelung der Sendungen eine Vollauslastung aller verwendeten Container bis auf einen zulässt, soll das Gewicht für die Teilladung berechnet werden, die diesem "letzten" Container theoretisch zufällt.

Konfiguration: