C# / .NET - replace last character in string

In this article, we would like to show you how to replace the last character in string in Java.

Quick solution: 

string originalString = "123";

string replaced = originalString.Substring(0, originalString.Length - 1) + "4";

Console.WriteLine(originalString); // 123
Console.WriteLine(replaced);       // 124

Practical examples

1. Using Substring() method

using System;

public class Program
{
    static string ReplaceLastLetter(string text, string newLetter)
    {
        string substring = text.Substring(0, text.Length - 1); // ABC -> AB
        return substring + newLetter; // ABD
    }

    public static void Main(string[] args)
    {
        string text = "ABC";
        string newLetter = "D";

        string replaced = ReplaceLastLetter(text, newLetter);

        Console.WriteLine(text);     // ABC
        Console.WriteLine(replaced); // ABD
    }
}

Output:

ABC
ABD

1. Using Remove() method

using System;

public class Program
{
    static string ReplaceLastLetter(string originalString, string newLetter)
    {
        string substring = originalString.Remove(originalString.Length - 1, 1); // ABC -> AB
        return substring + newLetter; // ABD
    }

    public static void Main(string[] args)
    {
        string originalString = "ABC";
        string newLetter = "D";

        string replaced = ReplaceLastLetter(originalString, newLetter);

        Console.WriteLine(originalString); // ABC
        Console.WriteLine(replaced);       // ABD
    }
}

Note:

Duplicated article: C#/.NET - replace last char in string

In the future, combine these 2 articles into one.

References

• String substring - C# Docs