Question

How to use Array.LastIndexOf() method to find the last index of a specified element in 1D Array in C#

Answer 1

using System;

namespace ConsoleApplication_C_Sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] arr = new String[6] { "aaa", "bbb", "ccc", "ddd", "eee", "aaa" };

            Console.WriteLine(Array.LastIndexOf(arr, "aaa"));
        }
    }
}


/*
run:
    
5
   
*/

 

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Answer 2

using System;

namespace ConsoleApplication_C_Sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] arr = new String[6] { "aaa", "bbb", "ccc", "ddd", "eee", "aaa" };

            Console.WriteLine(Array.LastIndexOf(arr, "aaa", 2));
        }
    }
}


/*
run:
    
0
   
*/

 

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Answer 3

using System;

namespace ConsoleApplication_C_Sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] arr = new String[7] { "aaa", "bbb", "ccc", "aaa", "ddd", "eee", "aaa" };

            // start index is greater than the end index because the search is done backward
            Console.WriteLine(Array.LastIndexOf(arr, "aaa", 5, 4));
        }
    }
}


/*
run:
    
3
   
*/

 

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