C# Enumerable Aggregate(IEnumerable, TAccumulate, Func, Func)

Description

Enumerable Aggregate(IEnumerable, TAccumulate, Func, Func)Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

Syntax

Enumerable.Aggregate(IEnumerable, TAccumulate, Func, Func) has the following syntax.

public static TResult Aggregate<TSource, TAccumulate, TResult>(
  this IEnumerable<TSource> source,
  TAccumulate seed,/* w w  w .  j  a  v a2  s  .c  om*/
  Func<TAccumulate, TSource, TAccumulate> func,
  Func<TAccumulate, TResult> resultSelector
)

Parameters

Enumerable.Aggregate(IEnumerable, TAccumulate, Func, Func) has the following parameters.

• TSource - The type of the elements of source.
• TAccumulate - The type of the accumulator value.
• TResult - The type of the resulting value.
• source - An IEnumerable to aggregate over.
• seed - The initial accumulator value.
• func - An accumulator function to be invoked on each element.
• resultSelector - A function to transform the final accumulator value into the result value.

Returns

returns TResult

Example

The following code example demonstrates how to use Aggregate to apply an accumulator function and a result selector.

/*  www  . j ava2  s .c om*/
using System;
using System.Linq;
using System.Collections.Generic;
public class MainClass{
  public static void Main(String[] argv){  
    string[] fruits = { "Java", "C#", "XML", "HTML", "Javascript" };
    // Determine whether any string in the array is longer than "XML".
    string longestName = fruits.Aggregate("XML",(longest, next) =>
                                        next.Length > longest.Length ? next : longest,
                                        fruit => fruit.ToUpper());
    
    Console.WriteLine("The fruit with the longest name is {0}.",longestName);
  }
}