Question

I can’t find a regex that matches repeated letters. My problem is that I want to use regex to filter out spam-mails, for example, I want to use regex to detect “spam” and “viagra” in these strings :
“xxxSpAmyyy”,
“xxxSPAMyyy”,
“xxxvI a Gr AA yyy”,
“xxxV iiA gR a xxx”

Do You have any suggestions how I do that in a good way?

Answer 1

This ignores the case, and it takes them whether they are one next to another, or there are other characters in between them

"(?i).{0,}v.{0,}i.{0,}a.{0,}g.{0,}r.{0,}a.{0,}"

If you know how many characters can be between the letters, you can enter .{0,max_distance} instead of .{0,}

UPDATE:

It works even for duplicates, as i have tried it:

    String str = "xxxV iiA gR a xxx";

    if(str.matches("(?i).{0,}v.{0,}i.{0,}a.{0,}g.{0,}r.{0,}a.{0,}")){
        System.out.println("Yes");
    }
    else{
        System.out.println("No");
    }

This prints Yes