Loyc.Collections.AListStatisticTracker< K, T, TSummary > Class Template Reference

This class efficiently lets you keep track of simple commutative statistics (such as total, average, sum of squares, and min/max) derived from the items of AList{T} and its variants (BList, BDictionary, and BMultiMap). More...

---

Source file:

• /Core/Loyc.Utilities/Collections/AListStatisticTracker.cs

Inheritance diagram for Loyc.Collections.AListStatisticTracker< K, T, TSummary >:

Remarks

This class efficiently lets you keep track of simple commutative statistics (such as total, average, sum of squares, and min/max) derived from the items of AList{T} and its variants (BList, BDictionary, and BMultiMap).

Note: this class relies on the "tree observer" feature of ALists, but SparseAList doesn't support tree observers as of 2020/01.

Typically a statistic tracker is created by calling an extension method on AList, BList, etc.

Public Member Functions
	AListStatisticTracker (Func< T, TSummary > selector, Func< TSummary[], TSummary > aggregator, TSummary emptyResult, AListBase< K, T > list=null)
	AListStatisticTracker (Func< T, TSummary > selector, Func< TSummary, TSummary, TSummary > aggregator, TSummary emptyResult, AListBase< K, T > list=null)
Public Member Functions inherited from Loyc.Collections.AListStatisticTrackerBase< K, T, TSummary >
TSummary	GetSummary ()
Public Member Functions inherited from Loyc.Collections.Impl.IAListTreeObserver< K, T >
void	Detach (AListBase< K, T > list, AListNode< K, T >?root)
	Called when the observer is being detached from an AList. Detach(), unlike Attach(), is not paired with a call to RootChanged. More...
void	RootChanged (AListBase< K, T > list, AListNode< K, T >?root, bool clear)
	Called when the root of the tree changes, or when the list is cleared. Also called after Attach(), but not after Detach(). More...

Protected Member Functions
override TSummary	Aggregate (TSummary[] data)
override TSummary	Summarize (AListLeafBase< K, T > data)
Protected Member Functions inherited from Loyc.Collections.AListStatisticTrackerBase< K, T, TSummary >
TSummary	GetSummary (AListNode< K, T > node)

Protected fields
override TSummary	EmptyResult => _emptyResult
Protected fields inherited from Loyc.Collections.AListStatisticTrackerBase< K, T, TSummary >
virtual TSummary	EmptyResult => Aggregate(Empty<TSummary>.Array)

Additional Inherited Members
Public fields inherited from Loyc.Collections.AListStatisticTrackerBase< K, T, TSummary >
IEnumerable< AListBase< K, T > >	AttachedLists => _roots.Keys
int	TotalCountInAttachedLists => _roots.Sum(pair => pair.Key.Count)
TSummary	Summary => GetSummary()