CSharp - LINQ Except

Introduction

The Except operator returns a sequence that contains all the elements of a first sequence that do not exist in a second sequence.

An element is determined to be equal to another element using their GetHashCode and Equals methods.

Prototypes

public static IEnumerable<T> Except<T>(
        this IEnumerable<T> first,
        IEnumerable<T> second);

Exceptions

ArgumentNullException is thrown if any arguments are null.

The following code shows how to use Except operator.

Demo

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
class Program//from   www  .  jav a 2 s. co  m
{
    static void Main(string[] args)
    {
        string[] codeNames = {"Python", "Java", "Javascript", "Bash", "C++", "Oracle"};
        
        //  First generate a processed sequence.
        IEnumerable<string> processed = codeNames.Take(4);
        
        IEnumerable<string> exceptions = codeNames.Except(processed);
        foreach (string name in exceptions)
            Console.WriteLine(name);
    }
}

Result