Example: SumNumbersInStringByRegex in Java

// SumNumbersInStringByRegex
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String inputString = "I have 10 apples, 5 bananas, and 2 dozens of grapes, costing $15 total.";
        int sum = 0;

        // Step 1: Define the regular expression pattern to find one or more digits
        Pattern pattern = Pattern.compile("\\d+");
        // Step 2: Create a Matcher object to find matches in the input string
        Matcher matcher = pattern.matcher(inputString);

        // Step 3: Loop while the matcher finds occurrences of the pattern
        while (matcher.find()) {
            // Step 4: Extract the matched sequence (which is a number string)
            String numberStr = matcher.group();
            // Step 5: Convert the number string to an integer and add to sum
            sum += Integer.parseInt(numberStr);
        }

        System.out.println("The original string is: \"" + inputString + "\"");
        System.out.println("Sum of numbers: " + sum);
    }
}