C# – Replace Last Occurrence of a String

The below code example shows you the way to replace the last occurrence of a string in C# (C Sharp).

using System;

namespace ByteNota
{
    class StringExample
    {
        static string ReplaceLast(string find, string replace, string str)
        {
            int lastIndex = str.LastIndexOf(find);

            if (lastIndex == -1)
            {
                return str;
            }

            string beginString = str.Substring(0, lastIndex);
            string endString = str.Substring(lastIndex + find.Length);

            return beginString + replace + endString;
        }

        static void Main(string[] args)
        {
            String str1 = "Hello World-";
            String newStr1 = ReplaceLast("-", "", str1);
            Console.WriteLine(newStr1); // Hello World

            String str2 = "Foo and Bar. Hello Bar";
            String newStr2 = ReplaceLast("Bar", "guys", str2);
            Console.WriteLine(newStr2); // Foo and Bar. Hello guys
        }

    }
}

Output:

Hello World
Foo and Bar. Hello guys