Question

How to use List.DefaultIfEmpty() to replace an empty list with a list of one default value in C#

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication_C_Sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> list = new List<int>();

            var d = list.DefaultIfEmpty();

            foreach (var n in d)
                Console.WriteLine(n);
        }
    }
}


/*
run:
     
0
 
*/

 

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Answer 2

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication_C_Sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> list = new List<int>();

            var d = list.DefaultIfEmpty(999);

            foreach (var n in d)
                Console.WriteLine(n);
        }
    }
}


/*
run:
     
999
 
*/

 

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