How do I get the last four characters from a string in C#?

Question

Suppose I have a string:

\"34234234d124\"

I want to get the last four characters of this string which is \"d124\". I can use <

Answer 1

Suggest using TakeLast method, for example: new String(text.TakeLast(4).ToArray())

Answer 2

This won't fail for any length string.

string mystring = "34234234d124";
string last4 = Regex.Match(mystring, "(?!.{5}).*").Value;
// last4 = "d124"
last4 = Regex.Match("d12", "(?!.{5}).*").Value;
// last4 = "d12"

This is probably overkill for the task at hand, but if there needs to be additional validation, it can possibly be added to the regular expression.

Edit: I think this regex would be more efficient:

@".{4}\Z"

Answer 3

Definition:

public static string GetLast(string source, int last)
{
     return last >= source.Length ? source : source.Substring(source.Length - last);
}

Usage:

GetLast("string of", 2);

Result:

of

Answer 4

Use a generic Last<T>. That will work with ANY IEnumerable, including string.

public static IEnumerable<T> Last<T>(this IEnumerable<T> enumerable, int nLastElements)
{
    int count = Math.Min(enumerable.Count(), nLastElements);
    for (int i = enumerable.Count() - count; i < enumerable.Count(); i++)
    {
        yield return enumerable.ElementAt(i);
    }
}

And a specific one for string:

public static string Right(this string str, int nLastElements)
{
    return new string(str.Last(nLastElements).ToArray());
}

Answer 5

You can use an extension method:

public static class StringExtension
{
    public static string GetLast(this string source, int tail_length)
    {
       if(tail_length >= source.Length)
          return source;
       return source.Substring(source.Length - tail_length);
    }
}

And then call:

string mystring = "34234234d124";
string res = mystring.GetLast(4);

Answer 6

A simple solution would be:

string mystring = "34234234d124";
string last4 = mystring.Substring(mystring.Length - 4, 4);