Enumerable.Aggregate Método

public:
generic <typename TSource, typename TAccumulate, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static TResult Aggregate(System::Collections::Generic::IEnumerable<TSource> ^ source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> ^ func, Func<TAccumulate, TResult> ^ resultSelector);

public static TResult Aggregate<TSource,TAccumulate,TResult> (this System.Collections.Generic.IEnumerable<TSource> source, TAccumulate seed, Func<TAccumulate,TSource,TAccumulate> func, Func<TAccumulate,TResult> resultSelector);

static member Aggregate : seq<'Source> * 'Accumulate * Func<'Accumulate, 'Source, 'Accumulate> * Func<'Accumulate, 'Result> -> 'Result

<Extension()>
Public Function Aggregate(Of TSource, TAccumulate, TResult) (source As IEnumerable(Of TSource), seed As TAccumulate, func As Func(Of TAccumulate, TSource, TAccumulate), resultSelector As Func(Of TAccumulate, TResult)) As TResult

Parámetros de tipo

Parámetros

Devoluciones

TResult

El valor final del acumulador transformado.The transformed final accumulator value.

Excepciones

Ejemplos

En el ejemplo de código siguiente se muestra cómo usar Aggregate para aplicar una función de acumulador y un selector de resultados.The following code example demonstrates how to use Aggregate to apply an accumulator function and a result selector.

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

// Determine whether any string in the array is longer than "banana".
string longestName =
    fruits.Aggregate("banana",
                    (longest, next) =>
                        next.Length > longest.Length ? next : longest,
    // Return the final result as an upper case string.
                    fruit => fruit.ToUpper());

Console.WriteLine(
    "The fruit with the longest name is {0}.",
    longestName);

// This code produces the following output:
//
// The fruit with the longest name is PASSIONFRUIT.

Sub AggregateEx3()
    Dim fruits() As String =
    {"apple", "mango", "orange", "passionfruit", "grape"}

    ' Determine whether any string in the array is longer than "banana".
    Dim longestName As String =
    fruits.Aggregate("banana",
                     Function(ByVal longest, ByVal fruit) _
                         IIf(fruit.Length > longest.Length, fruit, longest),
                     Function(ByVal fruit) fruit.ToUpper())

    ' Display the output.
    Console.WriteLine($"The fruit with the longest name is {longestName}")
End Sub

' This code produces the following output:
'
' The fruit with the longest name is PASSIONFRUIT

Comentarios

El Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>) método facilita la realización de un cálculo en una secuencia de valores.The Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>) method makes it simple to perform a calculation over a sequence of values. Este método funciona llamando a func una vez por cada elemento de source .This method works by calling func one time for each element in source. Cada vez func que se llama a, Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>) pasa el elemento de la secuencia y un valor agregado (como el primer argumento a func ).Each time func is called, Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>) passes both the element from the sequence and an aggregated value (as the first argument to func). El valor del seed parámetro se usa como el valor de agregado inicial.The value of the seed parameter is used as the initial aggregate value. El resultado de func reemplaza el valor agregado anterior.The result of func replaces the previous aggregated value. El resultado final de func se pasa a resultSelector para obtener el resultado final de Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>) .The final result of func is passed to resultSelector to obtain the final result of Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>).

Para simplificar las operaciones comunes de agregación, los operadores de consulta estándar también incluyen un método de recuento de uso general, Count y cuatro métodos de agregación numéricos, es decir Min ,, Max Sum y Average .To simplify common aggregation operations, the standard query operators also include a general purpose count method, Count, and four numeric aggregation methods, namely Min, Max, Sum, and Average.

public:
generic <typename TSource, typename TAccumulate>
[System::Runtime::CompilerServices::Extension]
 static TAccumulate Aggregate(System::Collections::Generic::IEnumerable<TSource> ^ source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> ^ func);

public static TAccumulate Aggregate<TSource,TAccumulate> (this System.Collections.Generic.IEnumerable<TSource> source, TAccumulate seed, Func<TAccumulate,TSource,TAccumulate> func);

static member Aggregate : seq<'Source> * 'Accumulate * Func<'Accumulate, 'Source, 'Accumulate> -> 'Accumulate

<Extension()>
Public Function Aggregate(Of TSource, TAccumulate) (source As IEnumerable(Of TSource), seed As TAccumulate, func As Func(Of TAccumulate, TSource, TAccumulate)) As TAccumulate

Parámetros de tipo

Parámetros

Devoluciones

TAccumulate

Valor final del acumulador.The final accumulator value.

Excepciones

Ejemplos

En el ejemplo de código siguiente se muestra cómo usar Aggregate para aplicar una función de acumulador y utilizar un valor de inicialización.The following code example demonstrates how to use Aggregate to apply an accumulator function and use a seed value.

int[] ints = { 4, 8, 8, 3, 9, 0, 7, 8, 2 };

// Count the even numbers in the array, using a seed value of 0.
int numEven = ints.Aggregate(0, (total, next) =>
                                    next % 2 == 0 ? total + 1 : total);

Console.WriteLine("The number of even integers is: {0}", numEven);

// This code produces the following output:
//
// The number of even integers is: 6

Sub AggregateEx2()
    ' Create an array of Integers.
    Dim ints() As Integer = {4, 8, 8, 3, 9, 0, 7, 8, 2}

    ' Count the even numbers in the array, using a seed value of 0.
    Dim numEven As Integer =
    ints.Aggregate(0,
                   Function(ByVal total, ByVal number) _
                       IIf(number Mod 2 = 0, total + 1, total))

    ' Display the output.
    Console.WriteLine($"The number of even integers is {numEven}")
End Sub

' This code produces the following output:
'
'The number of even integers is 6

Comentarios

El Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) método facilita la realización de un cálculo en una secuencia de valores.The Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) method makes it simple to perform a calculation over a sequence of values. Este método funciona llamando a func una vez por cada elemento de source .This method works by calling func one time for each element in source. Cada vez func que se llama a, Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) pasa el elemento de la secuencia y un valor agregado (como el primer argumento a func ).Each time func is called, Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) passes both the element from the sequence and an aggregated value (as the first argument to func). El valor del seed parámetro se usa como el valor de agregado inicial.The value of the seed parameter is used as the initial aggregate value. El resultado de func reemplaza el valor agregado anterior.The result of func replaces the previous aggregated value. Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) Devuelve el resultado final de func .Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>) returns the final result of func.

Para simplificar las operaciones comunes de agregación, los operadores de consulta estándar también incluyen un método de recuento de uso general, Count y cuatro métodos de agregación numéricos, es decir Min ,, Max Sum y Average .To simplify common aggregation operations, the standard query operators also include a general purpose count method, Count, and four numeric aggregation methods, namely Min, Max, Sum, and Average.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource Aggregate(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TSource, TSource> ^ func);

public static TSource Aggregate<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TSource,TSource> func);

static member Aggregate : seq<'Source> * Func<'Source, 'Source, 'Source> -> 'Source

<Extension()>
Public Function Aggregate(Of TSource) (source As IEnumerable(Of TSource), func As Func(Of TSource, TSource, TSource)) As TSource

Parámetros de tipo

Parámetros

Devoluciones

TSource

Valor final del acumulador.The final accumulator value.

Excepciones

Ejemplos

En el ejemplo de código siguiente se muestra cómo invertir el orden de las palabras en una cadena mediante Aggregate .The following code example demonstrates how to reverse the order of words in a string by using Aggregate.

string sentence = "the quick brown fox jumps over the lazy dog";

// Split the string into individual words.
string[] words = sentence.Split(' ');

// Prepend each word to the beginning of the
// new sentence to reverse the word order.
string reversed = words.Aggregate((workingSentence, next) =>
                                      next + " " + workingSentence);

Console.WriteLine(reversed);

// This code produces the following output:
//
// dog lazy the over jumps fox brown quick the

Sub AggregateEx1()
    Dim sentence As String =
    "the quick brown fox jumps over the lazy dog"
    ' Split the string into individual words.
    Dim words() As String = sentence.Split(" "c)
    ' Prepend each word to the beginning of the new sentence to reverse the word order.
    Dim reversed As String =
    words.Aggregate(Function(ByVal current, ByVal word) word & " " & current)

    ' Display the output.
    Console.WriteLine(reversed)
End Sub

' This code produces the following output:
'
' dog lazy the over jumps fox brown quick the

Comentarios

El Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) método facilita la realización de un cálculo en una secuencia de valores.The Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) method makes it simple to perform a calculation over a sequence of values. Este método funciona llamando a func una vez por cada elemento de, source excepto el primero.This method works by calling func one time for each element in source except the first one. Cada vez func que se llama a, Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) pasa el elemento de la secuencia y un valor agregado (como el primer argumento a func ).Each time func is called, Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) passes both the element from the sequence and an aggregated value (as the first argument to func). El primer elemento de source se utiliza como valor de agregado inicial.The first element of source is used as the initial aggregate value. El resultado de func reemplaza el valor agregado anterior.The result of func replaces the previous aggregated value. Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) Devuelve el resultado final de func .Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>) returns the final result of func.

Esta sobrecarga del Aggregate método no es adecuada para todos los casos porque usa el primer elemento de source como valor de agregado inicial.This overload of the Aggregate method isn't suitable for all cases because it uses the first element of source as the initial aggregate value. Debe elegir otra sobrecarga si el valor devuelto debe incluir solo los elementos de source que cumplen una condición determinada.You should choose another overload if the return value should include only the elements of source that meet a certain condition. Por ejemplo, esta sobrecarga no es confiable si desea calcular la suma de los números pares en source .For example, this overload isn't reliable if you want to calculate the sum of the even numbers in source. El resultado será incorrecto si el primer elemento es impar en lugar de incluso.The result will be incorrect if the first element is odd instead of even.

Para simplificar las operaciones comunes de agregación, los operadores de consulta estándar también incluyen un método de recuento de uso general, Count y cuatro métodos de agregación numéricos, es decir Min ,, Max Sum y Average .To simplify common aggregation operations, the standard query operators also include a general purpose count method, Count, and four numeric aggregation methods, namely Min, Max, Sum, and Average.