How to use Regex in Java to pattern match?

Question

I have read the documentation and various tutorials online but I\'m still confused on how regex works in Java. What I am trying to do is create a function which takes in ar

Answer 1

You will need to use Java's character class intersection operator inside a character class, otherwise it literally matches &&. Btw, your first character class from A to (lowercase) z also includes [\]^_, which you certainly do not want; and you misspelled "Patter.complile".

Also, matches()

Attempts to match the entire region against the pattern.

So you either need to use find() instead or pad the expression with .*.

public boolean checkString(String arg) {
    return Pattern.compile("[[a-zA-Z]&&[^MDCLXVIivxlcdm]]").matcher(arg).find();
}