Combine elements of an array, optionally summing specified properties. Written in ObjectScript.

ArrayCombineSum.cls

Class App.ArrayCombineSum Extends %RegisteredObject
{

ClassMethod createKey(array, keys) As %String
{
    	set output = ""
		set index = keys.Next("")
		while (index) {
			set key = keys.GetAt(index)
			set value = array.GetAt(key)
			if (value'="") {
				set output=output_array.GetAt(key)
			}
			set index = keys.Next(index)			
		}
		quit output
}

ClassMethod arrayCombineSum(ByRef data As %ListOfDataTypes, keys As %ListOfDataTypes, sumProperties As %ListOfDataTypes)
{
	set identityMap = ##class(%ArrayOfDataTypes).%New()
	set output = ##class(%ListOfDataTypes).%New()
	set key = data.Next("")
	
	while (key) {
		set item = data.GetAt(key)
		set pk = ..createKey(item, keys)
		if (identityMap.GetAt(pk)="") {
			do identityMap.SetAt(item,pk)	
			do output.Insert(item)
		}
		else {
			set existingItem = identityMap.GetAt(pk)
			set sumPropertiesIndex = sumProperties.Next("")
			while (sumPropertiesIndex) {
				set sumPropertiesKey = sumProperties.GetAt(sumPropertiesIndex)
				set itemValue = item.GetAt(sumPropertiesKey)
				set existingItemValue = existingItem.GetAt(sumPropertiesKey)
				set newValue = itemValue + existingItemValue
				do existingItem.SetAt(newValue, sumPropertiesKey)  
				do identityMap.SetAt(existingItem, pk)
				set sumPropertiesIndex = sumProperties.Next(sumPropertiesIndex)
			}
		}
		set key = data.Next(key)
	}
	
	set data = output
}

}