mystring.Substring（Math.Max​​（0，mystring.Length  -  4））;这//多少行是什么？
 

如果你是积极的字符串的长度至少是4，那么它更短：

  mystring.Substring（mystring.Length  -  4）;
 

Suppose I have a string:

string mystring = "34234234d124";

I want to get the last four characters of this string which is "d124". I can use SubString, but it needs a couple of lines of code.

Is it possible to get this result in one expression with C#?

mystring.Substring(Math.Max(0, mystring.Length - 4)); //how many lines is this?

If you're positive the length of your string is at least 4, then it's even shorter:

mystring.Substring(mystring.Length - 4);