Regex expression not working with once or none

Question

Below is my regex:

[^4\\d{3}-?\\d{4}-?\\d{4}-?\\d{4}$]

But it throws an error at -. I am using ?, which should al

Answer 1

Try escaping - with \ and remove [ and ]:

^4\d{3}\-?\d{4}\-?\d{4}\-?\d{4}$