LINQ

The custom calculation formula language is based on VB and can be extended with LINQ. Use LINQ if the pre-defined CC functions are not sufficient to do your calculations.

Please refer to Microsoft Visual basic LINQ documentation for more details.

Filter

The principle of filters is to filter a given list of items according to a predicate. To apply filter, you need:

• a list to filter

• a predicate (function taking a list item and returning a boolean)

The result is a new list with some of the items of input list.

NOTE

The number of items in the new list is smaller than in the input list.

Syntax:

• InputList.Where(Function(x) predicate)

• Where: to call the filter

• Function: to write the predicate

Example:

CurrentSignal.AllPeaks.Where(Function(p) p.Peak_Area>1.2 and p.Peak_Height<1000) returns a list of peaks with an area greater than 1.2 and height lower than 1000.

You can use this list in a formula to do the sum of the areas of all peaks in the list:

Sum("Peak_Area", CurrentSignal.AllPeaks.Where(Function(p) p.Peak_Area>1.2 And p.Peak_Height<1000))

Projection

The principle of projection is to create a list from a given list of items by transforming every item. To apply projection, you need:

• A list to transform

• A projection function (function taking a list item and returning a new item)

NOTE

The result is a new list of same length as input list. Item types can be different!

Syntax:

• InputList.Select(Function(x) projection)

• Select: to call the transformation

• Function: to write the projection function

Example:

CurrentSignal.AllPeaks.Select(Function(p) p.Peak_Area) returns a list of Peak_Area values from a list of peaks.

You can then do the sum: CurrentSignal.AllPeaks.Select(Function(p) p.Peak_Area).Sum()

Note that this is equivalent to the predefined Custom Calculation function Sum(“Peak_Area”, CurrentSignal.AllPeaks).

Aggregate

The principle of aggregate is to compute a single value from a list. To apply aggregation, you need:

• InputList.Select(Function(x) projection)

• A list to aggregate

• An accumulation function (function taking aggregate and current item)

• An initial value for aggregate

NOTE

The result is a unique aggregated value. The type of aggregated value can be different from item type.

Syntax:

• InputList.Aggregate(initial value,Function(acc,x) accumulation)

• Aggregate: to call the aggregation

• Function: to write the accumulation function

Examples:

(CurrentSignal.AllPeaks.Select(Function(p) p.Peak_Area)).Aggregate("", Function(acc,x) acc+" ; "&x) returns the list of all peaks area separated with a " ; ".

Note that this is equivalent to a VB function: string.join(" ; " ,CurrentSignal.AllPeaks.Select(Function(p) p.Peak_Area)).

 

(CurrentSignal.AllPeaks.Select(Function(p) p.Peak_Area)).Aggregate(0.0, Function(acc,x) acc+x) returns the sum of the peak areas.

Note that it is equivalent to the predefined Custom Calculation function Sum("Peak_Area", CurrentSignal.AllPeaks).