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 first 2 characters must be alphabetic and 2 last caracters must be numbers.

I tried many combinations and I didn’t have success. Last one I tried:

if(Regex.IsMatch(myString, "^[A-Za-z]{2}[0-9]{2}")){
}

Answer 1

You’re missing an ending anchor.

if(Regex.IsMatch(myString, "^[A-Za-z]{2}[0-9]{2}\z")) {
    // ...
}

Here’s a demo.

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EDIT: If you can have anything between an initial 2 letters and a final 2 numbers:

if(Regex.IsMatch(myString, @"^[A-Za-z]{2}.*\d{2}\z")) {
    // ...
}

Here’s a demo.