Regular Expression - 2 letters and 2 numbers in C#

Question

I am trying to develop a regular expression to validate a string that comes to me like: \"TE33\" or \"FR56\" or any sequence respecting 2 letters and 2 numbers.

The

Answer 1

Just for fun, here's a non-regex (more readable/maintainable for simpletons like me) solution:

string myString = "AB12";

if( Char.IsLetter(myString, 0) && 
    Char.IsLetter(myString, 1) && 
    Char.IsNumber(myString, 2) &&
    Char.IsNumber(myString, 3)) {
    // First two are letters, second two are numbers
}
else {
    // Validation failed
}

EDIT

It seems that I've misunderstood the requirements. The code below will ensure that the first two characters and last two characters of a string validate (so long as the length of the string is > 3)

string myString = "AB12";

if(myString.Length > 3) {    
    if( Char.IsLetter(myString, 0) && 
        Char.IsLetter(myString, 1) && 
        Char.IsNumber(myString, (myString.Length - 2)) &&
        Char.IsNumber(myString, (myString.Length - 1))) {
        // First two are letters, second two are numbers
      }
      else {
        // Validation failed
    }
}
else {
   // Validation failed
}