Queryable.Aggregate 메서드

정의

오버로드

Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence. 지정된 시드 값은 초기 누적기 값으로 사용되고 지정된 함수는 결과 값을 선택하는 데 사용됩니다.The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence. 지정된 시드 값은 초기 누적기 값으로 사용됩니다.The specified seed value is used as the initial accumulator value.

Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence.

Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence. 지정된 시드 값은 초기 누적기 값으로 사용되고 지정된 함수는 결과 값을 선택하는 데 사용됩니다.The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

public:
generic <typename TSource, typename TAccumulate, typename TResult>
[System::Runtime::CompilerServices::Extension]
 static TResult Aggregate(System::Linq::IQueryable<TSource> ^ source, TAccumulate seed, System::Linq::Expressions::Expression<Func<TAccumulate, TSource, TAccumulate> ^> ^ func, System::Linq::Expressions::Expression<Func<TAccumulate, TResult> ^> ^ selector);
public static TResult Aggregate<TSource,TAccumulate,TResult> (this System.Linq.IQueryable<TSource> source, TAccumulate seed, System.Linq.Expressions.Expression<Func<TAccumulate,TSource,TAccumulate>> func, System.Linq.Expressions.Expression<Func<TAccumulate,TResult>> selector);
static member Aggregate : System.Linq.IQueryable<'Source> * 'Accumulate * System.Linq.Expressions.Expression<Func<'Accumulate, 'Source, 'Accumulate>> * System.Linq.Expressions.Expression<Func<'Accumulate, 'Result>> -> 'Result
<Extension()>
Public Function Aggregate(Of TSource, TAccumulate, TResult) (source As IQueryable(Of TSource), seed As TAccumulate, func As Expression(Of Func(Of TAccumulate, TSource, TAccumulate)), selector As Expression(Of Func(Of TAccumulate, TResult))) As TResult

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

TAccumulate

누적기 값의 형식입니다.The type of the accumulator value.

TResult

결과 값의 형식입니다.The type of the resulting value.

매개 변수

source
IQueryable<TSource>

집계할 시퀀스입니다.A sequence to aggregate over.

seed
TAccumulate

초기 누적기 값입니다.The initial accumulator value.

func
Expression<Func<TAccumulate,TSource,TAccumulate>>

각 요소에 대해 호출할 누적기 함수입니다.An accumulator function to invoke on each element.

selector
Expression<Func<TAccumulate,TResult>>

최종 누적기 값을 결과 값으로 변환하는 함수입니다.A function to transform the final accumulator value into the result value.

반환

TResult

변환된 최종 누적기 값입니다.The transformed final accumulator value.

예외

source, func 또는 selectornull인 경우source or func or selector is null.

예제

다음 코드 예제에서는를 사용 하 여 Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) 누적기 함수와 결과 선택기를 적용 하는 방법을 보여 줍니다.The following code example demonstrates how to use Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) 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.AsQueryable().Aggregate(
    "banana",
    (longest, next) => next.Length > longest.Length ? next : longest,
    // Return the final result as an uppercase 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.

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.AsQueryable().Aggregate( _
    "banana", _
    Function(ByVal longest, ByVal fruit) IIf(fruit.Length > longest.Length, fruit, longest), _
    Function(ByVal fruit) fruit.ToUpper() _
)

MsgBox(String.Format( _
    "The fruit with the longest name is {0}.", longestName) _
)

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

설명

이 메서드에 형식 인수가 형식 중 하나인 형식의 매개 변수가 하나 이상 있습니다 Expression<TDelegate> Func<T,TResult> .This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 이러한 매개 변수는 람다 식을 전달할 수 있으며로 컴파일됩니다 Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>)메서드는 자신을 MethodCallExpression 생성 된 제네릭 메서드로 호출 하는을 생성 합니다 Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) .The Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) method generates a MethodCallExpression that represents calling Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) itself as a constructed generic method. 그런 다음 MethodCallExpression Execute<TResult>(Expression) IQueryProvider Provider 매개 변수의 속성이 나타내는의 메서드에를 전달 합니다 source .It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

호출을 나타내는 식 트리를 실행 한 결과로 발생 하는 쿼리 동작은 Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) 매개 변수의 형식 구현에 따라 달라 집니다 source .The query behavior that occurs as a result of executing an expression tree that represents calling Aggregate<TSource,TAccumulate,TResult>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>, Expression<Func<TAccumulate,TResult>>) depends on the implementation of the type of the source parameter. 예상 되는 동작은 지정 된 함수인가 func 소스 시퀀스의 각 값에 적용 되 고 누적 된 값이 반환 되는 것입니다.The expected behavior is that the specified function, func, is applied to each value in the source sequence and the accumulated value is returned. seed매개 변수는의 첫 번째 매개 변수에 해당 하는 누적 값의 초기값으로 사용 됩니다 func .The seed parameter is used as the seed value for the accumulated value, which corresponds to the first parameter in func. 최종 누적 값은에 전달 되어 selector 결과 값을 가져옵니다.The final accumulated value is passed to selector to obtain the result value.

일반적인 집계 작업을 단순화 하기 위해 표준 쿼리 연산자 집합에는 두 개의 계산 메서드 및 CountLongCount 4 개의 숫자 집계 메서드, 즉 Max ,, Min SumAverage 가 포함 됩니다.To simplify common aggregation operations, the set of standard query operators also includes two counting methods, Count and LongCount, and four numeric aggregation methods, namely Max, Min, Sum, and Average.

적용 대상

Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence. 지정된 시드 값은 초기 누적기 값으로 사용됩니다.The specified seed value is used as the initial accumulator value.

public:
generic <typename TSource, typename TAccumulate>
[System::Runtime::CompilerServices::Extension]
 static TAccumulate Aggregate(System::Linq::IQueryable<TSource> ^ source, TAccumulate seed, System::Linq::Expressions::Expression<Func<TAccumulate, TSource, TAccumulate> ^> ^ func);
public static TAccumulate Aggregate<TSource,TAccumulate> (this System.Linq.IQueryable<TSource> source, TAccumulate seed, System.Linq.Expressions.Expression<Func<TAccumulate,TSource,TAccumulate>> func);
static member Aggregate : System.Linq.IQueryable<'Source> * 'Accumulate * System.Linq.Expressions.Expression<Func<'Accumulate, 'Source, 'Accumulate>> -> 'Accumulate
<Extension()>
Public Function Aggregate(Of TSource, TAccumulate) (source As IQueryable(Of TSource), seed As TAccumulate, func As Expression(Of Func(Of TAccumulate, TSource, TAccumulate))) As TAccumulate

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

TAccumulate

누적기 값의 형식입니다.The type of the accumulator value.

매개 변수

source
IQueryable<TSource>

집계할 시퀀스입니다.A sequence to aggregate over.

seed
TAccumulate

초기 누적기 값입니다.The initial accumulator value.

func
Expression<Func<TAccumulate,TSource,TAccumulate>>

각 요소에 대해 호출할 누적기 함수입니다.An accumulator function to invoke on each element.

반환

TAccumulate

최종 누적기 값입니다.The final accumulator value.

예외

source 또는 funcnull인 경우source or func is null.

예제

다음 코드 예제에서는 Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) 함수에 시드 값이 제공 될 때를 사용 하 여 누적기 함수를 적용 하는 방법을 보여 줍니다.The following code example demonstrates how to use Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) to apply an accumulator function when a seed value is provided to the function.

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.AsQueryable().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

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.AsQueryable().Aggregate( _
        0, _
        Function(ByVal total, ByVal number) _
            IIf(number Mod 2 = 0, total + 1, total) _
    )

MsgBox(String.Format("The number of even integers is: {0}", numEven))

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

설명

이 메서드에 형식 인수가 형식 중 하나인 형식의 매개 변수가 하나 이상 있습니다 Expression<TDelegate> Func<T,TResult> .This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 이러한 매개 변수는 람다 식을 전달할 수 있으며로 컴파일됩니다 Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>)메서드는 자신을 MethodCallExpression 생성 된 제네릭 메서드로 호출 하는을 생성 합니다 Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) .The Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) method generates a MethodCallExpression that represents calling Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) itself as a constructed generic method. 그런 다음 MethodCallExpression Execute<TResult>(Expression) IQueryProvider Provider 매개 변수의 속성이 나타내는의 메서드에를 전달 합니다 source .It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

호출을 나타내는 식 트리를 실행 한 결과로 발생 하는 쿼리 동작은 Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) 매개 변수의 형식 구현에 따라 달라 집니다 source .The query behavior that occurs as a result of executing an expression tree that represents calling Aggregate<TSource,TAccumulate>(IQueryable<TSource>, TAccumulate, Expression<Func<TAccumulate,TSource,TAccumulate>>) depends on the implementation of the type of the source parameter. 예상 되는 동작은 지정 된 함수인가 func 소스 시퀀스의 각 값에 적용 되 고 누적 된 값이 반환 되는 것입니다.The expected behavior is that the specified function, func, is applied to each value in the source sequence and the accumulated value is returned. seed매개 변수는의 첫 번째 매개 변수에 해당 하는 누적 값의 초기값으로 사용 됩니다 func .The seed parameter is used as the seed value for the accumulated value, which corresponds to the first parameter in func.

일반적인 집계 작업을 단순화 하기 위해 표준 쿼리 연산자 집합에는 두 개의 계산 메서드 및 CountLongCount 4 개의 숫자 집계 메서드, 즉 Max ,, Min SumAverage 가 포함 됩니다.To simplify common aggregation operations, the set of standard query operators also includes two counting methods, Count and LongCount, and four numeric aggregation methods, namely Max, Min, Sum, and Average.

적용 대상

Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>)

시퀀스에 누적기 함수를 적용합니다.Applies an accumulator function over a sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource Aggregate(System::Linq::IQueryable<TSource> ^ source, System::Linq::Expressions::Expression<Func<TSource, TSource, TSource> ^> ^ func);
public static TSource Aggregate<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TSource,TSource>> func);
static member Aggregate : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, 'Source, 'Source>> -> 'Source
<Extension()>
Public Function Aggregate(Of TSource) (source As IQueryable(Of TSource), func As Expression(Of Func(Of TSource, TSource, TSource))) As TSource

형식 매개 변수

TSource

source 요소의 형식입니다.The type of the elements of source.

매개 변수

source
IQueryable<TSource>

집계할 시퀀스입니다.A sequence to aggregate over.

func
Expression<Func<TSource,TSource,TSource>>

각 요소에 적용할 누적기 함수입니다.An accumulator function to apply to each element.

반환

TSource

최종 누적기 값입니다.The final accumulator value.

예외

source 또는 funcnull인 경우source or func is null.

source에 요소가 없는 경우source contains no elements.

예제

다음 코드 예제에서는를 사용 하 여 Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) 문자열 배열에서 문장을 빌드하는 방법을 보여 줍니다.The following code example demonstrates how to use Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) to build a sentence from an array of strings.

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

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

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

Console.WriteLine(reversed);

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

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)

' Use Aggregate() to prepend each word to the beginning of the 
' new sentence to reverse the word order.
Dim reversed As String = _
    words.AsQueryable().Aggregate( _
        Function(ByVal workingSentence, ByVal nextWord) nextWord & " " & workingSentence _
    )

MsgBox(reversed)

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

설명

이 메서드에 형식 인수가 형식 중 하나인 형식의 매개 변수가 하나 이상 있습니다 Expression<TDelegate> Func<T,TResult> .This method has at least one parameter of type Expression<TDelegate> whose type argument is one of the Func<T,TResult> types. 이러한 매개 변수는 람다 식을 전달할 수 있으며로 컴파일됩니다 Expression<TDelegate> .For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<TDelegate>.

Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>)메서드는 자신을 MethodCallExpression 생성 된 제네릭 메서드로 호출 하는을 생성 합니다 Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) .The Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) method generates a MethodCallExpression that represents calling Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) itself as a constructed generic method. 그런 다음 MethodCallExpression Execute<TResult>(Expression) IQueryProvider Provider 매개 변수의 속성이 나타내는의 메서드에를 전달 합니다 source .It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

호출을 나타내는 식 트리를 실행 한 결과로 발생 하는 쿼리 동작은 Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) 매개 변수의 형식 구현에 따라 달라 집니다 source .The query behavior that occurs as a result of executing an expression tree that represents calling Aggregate<TSource>(IQueryable<TSource>, Expression<Func<TSource,TSource,TSource>>) depends on the implementation of the type of the source parameter. 예상 되는 동작은 지정 된 함수인가 func 소스 시퀀스의 각 값에 적용 되 고 누적 된 값이 반환 되는 것입니다.The expected behavior is that the specified function, func, is applied to each value in the source sequence and the accumulated value is returned. 의 첫 번째 값은 source 의 첫 번째 매개 변수에 해당 하는 누적 값의 초기값으로 사용 됩니다 func .The first value in source is used as the seed value for the accumulated value, which corresponds to the first parameter in func.

일반적인 집계 작업을 단순화 하기 위해 표준 쿼리 연산자 집합에는 두 개의 계산 메서드 및 CountLongCount 4 개의 숫자 집계 메서드, 즉 Max ,, Min SumAverage 가 포함 됩니다.To simplify common aggregation operations, the set of standard query operators also includes two counting methods, Count and LongCount, and four numeric aggregation methods, namely Max, Min, Sum, and Average.

적용 대상