Enumerable.Count Enumerable.Count Enumerable.Count Enumerable.Count Method

Définition

Retourne le nombre total d'éléments dans une séquence.Returns the number of elements in a sequence.

Surcharges

Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>)

Retourne le nombre total d'éléments dans une séquence.Returns the number of elements in a sequence.

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

Retourne un nombre qui représente les éléments de la séquence spécifiée qui satisfont à une condition.Returns a number that represents how many elements in the specified sequence satisfy a condition.

Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>) Count<TSource>(IEnumerable<TSource>)

Retourne le nombre total d'éléments dans une séquence.Returns the number of elements in a sequence.

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

Paramètres de type

TSource

Le type des éléments de source.The type of the elements of source.

Paramètres

source
IEnumerable<TSource>

Séquence qui contient les éléments à compter.A sequence that contains elements to be counted.

Retours

Nombre total d'éléments dans la séquence d'entrée.The number of elements in the input sequence.

Exceptions

Le nombre d'éléments dans source est supérieur à MaxValue.The number of elements in source is larger than MaxValue.

Exemples

L’exemple de code suivant montre comment utiliser Count<TSource>(IEnumerable<TSource>) pour compter les éléments dans un tableau.The following code example demonstrates how to use Count<TSource>(IEnumerable<TSource>) to count the elements in an array.

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

try
{
    int numberOfFruits = fruits.Count();
    Console.WriteLine(
        "There are {0} fruits in the collection.",
        numberOfFruits);

}
catch (OverflowException)
{
    Console.WriteLine("The count is too large to store as an Int32.");
    Console.WriteLine("Try using the LongCount() method instead.");
}

// 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"}

Try
    ' Count the number of items in the array.
    Dim numberOfFruits As Integer = fruits.Count()
    ' Display the output.
    MsgBox("There are " & numberOfFruits & " fruits in the collection.")
Catch e As OverflowException
    MsgBox("The count is too large to store as an Int32. Try using LongCount() instead.")
End Try

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

Remarques

Si le type de source implémente ICollection<T>, cette implémentation est utilisée pour obtenir le nombre d’éléments.If the type of source implements ICollection<T>, that implementation is used to obtain the count of elements. Sinon, cette méthode détermine le nombre.Otherwise, this method determines the count.

Utilisez le LongCount méthode si vous souhaitez autoriser le résultat peut être supérieur à MaxValue.Use the LongCount method when you expect and want to allow the result to be greater than MaxValue.

Dans la syntaxe d’expression de requête Visual Basic, un Aggregate Into Count() clause se traduit par un appel à Count.In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.

Voir aussi

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

Retourne un nombre qui représente les éléments de la séquence spécifiée qui satisfont à une condition.Returns a number that represents how many elements in the specified sequence satisfy a condition.

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

Paramètres de type

TSource

Le type des éléments de source.The type of the elements of source.

Paramètres

source
IEnumerable<TSource>

Séquence qui contient les éléments à tester et à compter.A sequence that contains elements to be tested and counted.

predicate
Func<TSource,Boolean>

Fonction permettant de tester chaque élément par rapport à une condition.A function to test each element for a condition.

Retours

Nombre qui représente les éléments de la séquence spécifiée qui satisfont à la condition dans la fonction de prédicat.A number that represents how many elements in the sequence satisfy the condition in the predicate function.

Exceptions

source ou predicate est null.source or predicate is null.

Le nombre d'éléments dans source est supérieur à MaxValue.The number of elements in source is larger than MaxValue.

Exemples

L’exemple de code suivant montre comment utiliser Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) pour compter les éléments dans un tableau qui remplissent une condition.The following code example demonstrates how to use Count<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 bool Vaccinated { get; set; }
}

public static void CountEx2()
{
    Pet[] pets = { new Pet { Name="Barley", Vaccinated=true },
                   new Pet { Name="Boots", Vaccinated=false },
                   new Pet { Name="Whiskers", Vaccinated=false } };

    try
    {
        int numberUnvaccinated = pets.Count(p => p.Vaccinated == false);
        Console.WriteLine("There are {0} unvaccinated animals.", numberUnvaccinated);
    }
    catch (OverflowException)
    {
        Console.WriteLine("The count is too large to store as an Int32.");
        Console.WriteLine("Try using the LongCount() method instead.");
    }
}

// This code produces the following output:
//
// There are 2 unvaccinated animals.
Structure Pet
    Public Name As String
    Public Vaccinated As Boolean
End Structure

Public Shared Sub CountEx2()
    ' Create an array of Pet objects.
    Dim pets() As Pet = {New Pet With {.Name = "Barley", .Vaccinated = True},
                 New Pet With {.Name = "Boots", .Vaccinated = False},
                 New Pet With {.Name = "Whiskers", .Vaccinated = False}}

    Try
        ' Count the number of Pets in the array where the Vaccinated property is False.
        Dim numberUnvaccinated As Integer =
    pets.Count(Function(p) p.Vaccinated = False)
        ' Display the output.
        MsgBox("There are " & numberUnvaccinated & " unvaccinated animals.")
    Catch e As OverflowException
        MsgBox("The count is too large to store as an Int32. Try using LongCount() instead.")
    End Try

End Sub

' This code produces the following output:
'
' There are 2 unvaccinated animals.

Remarques

Si le type de source implémente ICollection<T>, cette implémentation est utilisée pour obtenir le nombre d’éléments.If the type of source implements ICollection<T>, that implementation is used to obtain the count of elements. Sinon, cette méthode détermine le nombre.Otherwise, this method determines the count.

Vous devez utiliser le LongCount méthode si vous souhaitez autoriser le résultat peut être supérieur à MaxValue.You should use the LongCount method when you expect and want to allow the result to be greater than MaxValue.

Dans la syntaxe d’expression de requête Visual Basic, un Aggregate Into Count() clause se traduit par un appel à Count.In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.

Voir aussi

S’applique à