Enumerable.Count(TSource) Method (IEnumerable(TSource), Func(TSource, Boolean))
Returns a number that represents how many elements in the specified sequence satisfy a condition.
Assembly: System.Core (in System.Core.dll)
static member Count : source:IEnumerable<'TSource> * predicate:Func<'TSource, bool> -> int
The type of the elements of source.
- Type: System.Collections.Generic.IEnumerable()
A sequence that contains elements to be tested and counted.
Return ValueType: System.Int32
A number that represents how many elements in the sequence satisfy the condition in the predicate function.
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(). When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).
If the type of source implements ICollection(T), that implementation is used to obtain the count of elements. Otherwise, this method determines the count.
In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.