Question

I have the following aaaa_bb_cc string to match and written a regex pattern like

\\w{4}+\\_\\w{2}\\_\\w{2} and it works. Is there any simple regex which can do this same ?

Answer 1

I sometimes do what I call “meta-regexing” as follows:

    String pattern = "x{4}_x{2}_x{2}".replace("x", "[a-z]");
    System.out.println(pattern); // prints "[a-z]{4}_[a-z]{2}_[a-z]{2}"

Note that this doesn’t use \w, which can match an underscore. That is, your original pattern would match "__________".

If x really needs to be replaced with [a-zA-Z0-9], then just do it in the one place (instead of 3 places).

Other examples

• Regex for metamap in Java
• How do I convert CamelCase into human-readable names in Java?