Regex:
^[U][S][A]\d{2}[C][S]\d{3}
It indicates these values are valid:
USA25CS131 (valid)
USA25CS1311 (invalid length)
How do I get it to reject a string that's too long?
2 Answers
You can simply anchor the regex at the end with $, like this:
^[U][S][A]\d{2}[C][S]\d{3}$
and now you won't match strings with extra characters at the end.
You can also simplify your regex to this:
^USA\d{2}CS\d{3}$
Comments
^\w{1,10}$
That will match on anything 1-10 characters long, ^ means start of the line and $ means end of the line. You can adapt this with your code to produce the results you want.
Given your specific regex I would use ^[U][S][A]\d{2}[C][S]\d{3}$(just adding $ to the end)
[U]is equal toU. So either have[USA]{3}which can be anything fromSSStoUUUor just typeUSA.