java - Get the index of a pattern in a string using regex

Question

I want to search a string for a specific pattern.

Do the regular expression classes provide the positions (indexes within the string) of the pattern within the string?
There can be more that 1 occurences of the pattern.
Any practical example?

Answer 1

Use Matcher:

public static void printMatches(String text, String regex) {
    Pattern pattern = Pattern.compile(regex);
    Matcher matcher = pattern.matcher(text);
    // Check all occurrences
    while (matcher.find()) {
        System.out.print("Start index: " + matcher.start());
        System.out.print(" End index: " + matcher.end());
        System.out.println(" Found: " + matcher.group());
    }
}