How to get last 4 characters from string innC#?

Getting the last 4 characters from a string in C# is a common task that can be accomplished using the Substring() method. This method extracts a portion of the string based on the starting position and length specified.

Syntax

Following is the syntax for using Substring() to get the last characters −

string.Substring(startIndex)
string.Substring(startIndex, length)

To get the last 4 characters, calculate the starting position as −

str.Substring(str.Length - 4)

Using Substring() Method

The Substring() method extracts characters from a specified starting position to the end of the string. To get the last 4 characters, we start from str.Length - 4 position −

using System;

public class Demo {
    public static void Main() {
        string str = "Football and Tennis";
        string res = str.Substring(str.Length - 4);
        Console.WriteLine("Original string: " + str);
        Console.WriteLine("Last 4 characters: " + res);
    }
}

The output of the above code is −

Original string: Football and Tennis
Last 4 characters: nnis

Using Take() Method with LINQ

Another approach is using LINQ's Skip() and Take() methods to get the last characters −

using System;
using System.Linq;

public class Demo {
    public static void Main() {
        string str = "Programming";
        string last4 = new string(str.Skip(str.Length - 4).ToArray());
        Console.WriteLine("Original string: " + str);
        Console.WriteLine("Last 4 characters: " + last4);
    }
}

The output of the above code is −

Original string: Programming
Last 4 characters: ming

Handling Edge Cases

When working with strings shorter than 4 characters, it's important to add proper validation to avoid exceptions −

using System;

public class Demo {
    public static string GetLast4Characters(string input) {
        if (string.IsNullOrEmpty(input)) {
            return "";
        }
        return input.Length >= 4 ? input.Substring(input.Length - 4) : input;
    }
    
    public static void Main() {
        string[] testStrings = {"Hello World", "C#", "Code", "Programming"};
        
        foreach (string str in testStrings) {
            string result = GetLast4Characters(str);
            Console.WriteLine($"'{str}' -> Last 4: '{result}'");
        }
    }
}

The output of the above code is −

'Hello World' -> Last 4: 'orld'
'C#' -> Last 4: 'C#'
'Code' -> Last 4: 'Code'
'Programming' -> Last 4: 'ming'

Conclusion

The Substring() method is the most straightforward way to extract the last 4 characters from a string in C#. Always validate string length to prevent ArgumentOutOfRangeException when working with strings shorter than the desired character count.