Question

I’m trying to get the indexes for each pattern that I find in a document. So far I have:

    String temp = "This is a test to see HelloWorld in a test that sees HelloWorld in a test";
    Pattern pattern = Pattern.compile("HelloWorld");
    Matcher matcher = pattern.matcher(temp);
    int current = 0;
    int start;
    int end;

    while (matcher.find()) {
        start = matcher.start(current);
        end = matcher.end(current);
        System.out.println(temp.substring(start, end));
        current++;
    }

For some reason it keeps finding only the first instance of HelloWorld in temp though which results in an infinite loop. To be honest, I wasn’t sure if you could use matcher.start(current) and matcher.end(current) – it was just a wild guess because matcher.group(current) worked before. This time I need the actual indexes though so matcher.group() wouldn’t work for me.

Answer 1

Modify the regex to look like this:

while (matcher.find()) {
    start = matcher.start();
    end = matcher.end();
    System.out.println(temp.substring(start, end));
}