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Picks a random subset of count items from collection, and places
those items into a random order. No item is selected more than once.
Namespace: Wintellect.PowerCollections
Assembly:
PowerCollections (in PowerCollections.dll)
Syntax
| C# |
|---|
public static T[] RandomSubset<T>( IEnumerable<T> collection, int count, Random randomGenerator ) |
| Visual Basic (Declaration) |
|---|
Public Shared Function RandomSubset(Of T) ( _ collection As IEnumerable(Of T), _ count As Integer, _ randomGenerator As Random _ ) As T() |
| Visual C++ |
|---|
public: generic<typename T> static array<T>^ RandomSubset ( IEnumerable<T>^ collection, int count, Random^ randomGenerator ) |
Parameters
- collection
- IEnumerable<(Of <T>)>
The collection of items to select from. This collection is not changed.
- count
- Int32
The number of items in the subset to choose.
- randomGenerator
- Random
The random number generates used to make the selection.
Return Value
An array of count items, selected at random from collection.Type Parameters
- T
- The type of items in the collection.
Remarks
If the collection implements IList<T>, then this method takes time O(count).
Otherwise, this method takes time O(N), where N is the number of items in the collection.
Exceptions
| Exception | Condition |
|---|---|
| System..::ArgumentOutOfRangeException | count is negative or greater than collection.Count. |
| System..::ArgumentNullException | randomGenerator is null. |
See Also
Algorithms Class
Wintellect.PowerCollections Namespace
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