Enumerable.LongCount Enumerable.LongCount Enumerable.LongCount Enumerable.LongCount Method

Definition

Restituisce un oggetto Int64 che rappresenta il numero di elementi in una sequenza. Returns an Int64 that represents the number of elements in a sequence.

Overloads

LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Restituisce un oggetto Int64 che rappresenta quanti elementi in una sequenza soddisfano una condizione. Returns an Int64 that represents how many elements in a sequence satisfy a condition.

LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>)

Restituisce un oggetto Int64 che rappresenta il numero totale di elementi in una sequenza. Returns an Int64 that represents the total number of elements in a sequence.

LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Restituisce un oggetto Int64 che rappresenta quanti elementi in una sequenza soddisfano una condizione. Returns an Int64 that represents how many elements in a sequence satisfy a condition.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static long LongCount(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, bool> ^ predicate);
public static long LongCount<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,bool> predicate);
static member LongCount : seq<'Source> * Func<'Source, bool> -> int64
<Extension()>
Public Function LongCount(Of TSource) (source As IEnumerable(Of TSource), predicate As Func(Of TSource, Boolean)) As Long

Type Parameters

TSource

Il tipo degli elementi della origine. The type of the elements of source.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> che contiene gli elementi da contare. An IEnumerable<T> that contains the elements to be counted.

predicate
Func<TSource,Boolean>

Funzione per testare ogni elemento rispetto a una condizione. A function to test each element for a condition.

Returns

Numero che rappresenta quanti elementi nella sequenza specificata soddisfano la condizione nella funzione predicato. A number that represents how many elements in the sequence satisfy the condition in the predicate function.

Exceptions

source o predicate è null. source or predicate is null.

Il numero di elementi corrispondenti è maggiore di MaxValue. The number of matching elements exceeds MaxValue.

Examples

Esempio di codice seguente viene illustrato come utilizzare LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) per contare gli elementi in una matrice che soddisfa una condizione.The following code example demonstrates how to use LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) to count the elements in an array that satisfy a condition.

class Pet
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public static void LongCountEx2()
{
    Pet[] pets = { new Pet { Name="Barley", Age=8 },
                   new Pet { Name="Boots", Age=4 },
                   new Pet { Name="Whiskers", Age=1 } };

    const int Age = 3;

    long count = pets.LongCount(pet => pet.Age > Age);

    Console.WriteLine("There are {0} animals over age {1}.", count, Age);
}

/*
 This code produces the following output:

 There are 2 animals over age 3.
*/

Structure Pet
    Public Name As String
    Public Age As Integer
End Structure

Sub LongCountEx2()
    ' Create a list of Pet objects.
    Dim pets As New List(Of Pet)(New Pet() _
                 {New Pet With {.Name = "Barley", .Age = 8},
                  New Pet With {.Name = "Boots", .Age = 4},
                  New Pet With {.Name = "Whiskers", .Age = 1}})

    ' Determine the number of elements in the list
    ' where the pet's age is greater than a constant value (3).
    Const Age As Integer = 3
    Dim count As Long =
pets.LongCount(Function(pet) pet.Age > Age)

    ' Display the result.
    MsgBox("There are " & count & " animals over age " & Age)
End Sub

' This code produces the following output:
'
' There are 2 animals over age 3

Remarks

Usare questo metodo invece Count quando ci si aspetta che il risultato può essere maggiore MaxValue.Use this method rather than Count when you expect the result to be greater than MaxValue.

In Visual Basic sintassi delle espressioni di query, un Aggregate Into LongCount() clausola viene convertita in una chiamata di LongCount.In Visual Basic query expression syntax, an Aggregate Into LongCount() clause translates to an invocation of LongCount.

See Also

LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>) LongCount<TSource>(IEnumerable<TSource>)

Restituisce un oggetto Int64 che rappresenta il numero totale di elementi in una sequenza. Returns an Int64 that represents the total number of elements in a sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static long LongCount(System::Collections::Generic::IEnumerable<TSource> ^ source);
public static long LongCount<TSource> (this System.Collections.Generic.IEnumerable<TSource> source);
static member LongCount : seq<'Source> -> int64
<Extension()>
Public Function LongCount(Of TSource) (source As IEnumerable(Of TSource)) As Long

Type Parameters

TSource

Il tipo degli elementi della origine. The type of the elements of source.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> che contiene gli elementi da contare. An IEnumerable<T> that contains the elements to be counted.

Returns

Numero di elementi nella sequenza di origine. The number of elements in the source sequence.

Exceptions

Il numero di elementi è maggiore di MaxValue. The number of elements exceeds MaxValue.

Examples

Esempio di codice seguente viene illustrato come utilizzare LongCount<TSource>(IEnumerable<TSource>) per contare gli elementi in una matrice.The following code example demonstrates how to use LongCount<TSource>(IEnumerable<TSource>) to count the elements in an array.

string[] fruits = { "apple", "banana", "mango", 
                      "orange", "passionfruit", "grape" };

long count = fruits.LongCount();

Console.WriteLine("There are {0} fruits in the collection.", count);

/*
 This code produces the following output:

 There are 6 fruits in the collection.
*/

' Create an array of strings.
Dim fruits() As String =
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}

' Get the number of items in the array.
Dim count As Long = fruits.LongCount()

' Display the result.
MsgBox("There are " & count & " fruits in the collection.")

' This code produces the following output:
'
' There are 6 fruits in the collection.

Remarks

Usare questo metodo invece Count quando ci si aspetta che il risultato può essere maggiore MaxValue.Use this method rather than Count when you expect the result to be greater than MaxValue.

In Visual Basic sintassi delle espressioni di query, un Aggregate Into LongCount() clausola viene convertita in una chiamata di LongCount.In Visual Basic query expression syntax, an Aggregate Into LongCount() clause translates to an invocation of LongCount.

See Also

Applies to