Parsing Strings – Introduction to Programming

Parsing is the process of splitting a string into smaller substrings (a.k.a. tokens).
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/*
 * Changing the delimiter on the Scanner.
 */
public static void parseColonDelin(Scanner sc) {
    sc.useDelimiter(":|\n");
    while(sc.hasNext()) {
        String token = sc.next();
        System.out.println("[" + token + "]");
    }
}

/*
 * Reading each line of input as a String, splitting the String, 
 * and putting the tokens in an array.
 */
public static void parseTabDelin(Scanner sc) {
    if (!sc.hasNext())
        return;
 
    while(sc.hasNext()) {
        String input = sc.nextLine();
        String[] tokens = input.split("\t|\n");
        for(String token : tokens)
            System.out.println("[" + token + "]");
    }
}

/*
 * Reading each line as a String, creating a regex Pattern,
 * and using a Matcher to find instances of the pattern in 
 * the String.
 */
public static void parseFixedLen(Scanner sc) {
    if (!sc.hasNext())
        return;

    while(sc.hasNext()) {
        String input = sc.nextLine();
        Pattern p = Pattern.compile("[PKHT]\\d\\d");
        Matcher m = p.matcher(input);
        while (m.find()) {
            String token = m.group();
            System.out.println("[" + token + "]");
        }
    }
}