Java Regex Word Boundaries

Question

Hi I have the following code which is meant to find the word "is" but not when it is within another string so the word "this" should not return a match so I use \b. But the following code does not find a match and I cant figure out why?

public static void main(String[] args) {
    String a = "This island is beautiful.";
    Pattern p = Pattern.compile("\bis\b");
    Matcher m = p.matcher(a);

    while(m.find()){

        System.out.println(a.substring(m.start(), m.end()));
    }

}

Honour

Instead of a.substring(m.start(), m.end()) you could just write m.group(). – Schoolgirl

Answer 1

Double escape it:

Pattern p = Pattern.compile("\\bis\\b");

Regex in Java requires you to doubly escape certain special regex symbols, one escaping for Java and another for underlying regex engine.

Zhdanov

No need to be since \b doesn't generate compile time error as \s or \w etc. – Zhdanov

He already had the word boundry, just needed to escape the escape for a double quoted string. – Informed