Quantifier Operators in linq C#

Quantifier query operators’ works on only single input sequence and return single Boolean value.

Contains 

The Contains query operator evaluates the elements in the input sequence and returns true if a specified value exists.

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LINQTutorial
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] items = { "item1", "item2", "item3" };
            //return true
            var item = items.Contains("item2");

            //return false
            var item1 = items.Contains("item4");

            Console.WriteLine("Result is " + item +" Missing Item "+item1);
            Console.ReadLine();
        }
    }
}

 

Any

Any operator works in two ways or we can say that there are two overloaded version of any operator.

1. Any return true if any element is exists in list.
2. If predicate or lambda expression is used then any operator return true when element is matched in list which satisfied the specified predicate condition.

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LINQTutorial
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] items = { };
            var result = items.Any();
            //It will return because items array does not have any element.
            Console.WriteLine("items in Items array are exists " + result);

            int[] numbers = { 2, 3, 4, 5, 9, 10 };
            //Check element which are divisble by 3 completely.
            var numexists = numbers.Any(i => i % 3 == 0);
            Console.WriteLine("Elements are divisible by 3" + numexists);
            Console.ReadLine();
        }
    }
}

 

All

The All query operator takes a predicate and evaluates the elements in the input sequence to determine if every element satisfies this predicate.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LINQTutorial
{
    class Program
    {
        static void Main(string[] args)
        {
           

            int[] numbers = { 2, 3, 4, 5, 9, 10 };
          //This will return false because all elements in numbers are not completely divisble by 3
            var numexists = numbers.All(i => i % 3 == 0);
            Console.WriteLine("Elements are divisible by 3" + numexists);
            Console.ReadLine();
        }
    }
}

 

SequenceEqual

The SequenceEqual query operator compares two sequences to see if they both have exactly the same elements in the same order.

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LINQTutorial
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] items1 = {"item1","item2","item2" };


            string[] items2 = { "item1", "item2", "item2" };
            //Check element which are divisble by 3 completely.
            var sameitems = items1.SequenceEqual(items2);
            Console.WriteLine("Both List have same items "+sameitems);
            Console.ReadLine();
        }
    }
}