How do I use a delimiter with Scanner useDelimiter in Java

Question

sc   new Scanner new File dataFile    sc useDelimiter     r n      I don t understand how delimiter works  can someone explain this in layman terms

User · Answer

With Scanner the default delimiters are the whitespace characters.

But Scanner can define where a token starts and ends based on a set of delimiter, wich could be specified in two ways:

Using the Scanner method: useDelimiter(String pattern)
Using the Scanner method : useDelimiter(Pattern pattern) where Pattern is a regular expression that specifies the delimiter set.

So useDelimiter() methods are used to tokenize the Scanner input, and behave like StringTokenizer class, take a look at these tutorials for further information:

And here is an Example:

public static void main(String[] args) {

    // Initialize Scanner object
    Scanner scan = new Scanner("Anna Mills/Female/18");
    // initialize the string delimiter
    scan.useDelimiter("/");
    // Printing the tokenized Strings
    while(scan.hasNext()){
        System.out.println(scan.next());
    }
    // closing the scanner stream
    scan.close();
}

Prints this output:

Anna Mills
Female
18

User · Answer

For example   String myInput   null  Scanner myscan   new Scanner System in  useDelimiter    n    System out println  Enter your input      myInput   myscan next    System out println myInput     This will let you use Enter as a delimiter   Thus  if you input   Hello world  ENTER    it will print  Hello World

User · Answer

The scanner can also use delimiters other than whitespace   Easy example from Scanner API   String input    quot 1 fish 2 fish red fish blue fish quot          s  means 0 or more repetitions of any whitespace character      fish is the pattern to find  Scanner s   new Scanner input  useDelimiter  quot   s fish  s  quot      System out println s nextInt          prints  1  System out println s nextInt          prints  2  System out println s next             prints  red  System out println s next             prints  blue      don t forget to close the scanner    s close      The point is to understand the regular expressions  regex  inside the Scanner  useDelimiter  Find an useDelimiter tutorial here   To start with regular expressions here you can find a nice tutorial  Notes abc       Letters 123       Digits  d      Any Digit  D      Any Non-digit character         Any Character         Period  abc    Only a  b  or c   abc   Not a  b  nor c  a-z    Characters a to z  0-9    Numbers 0 to 9  w      Any Alphanumeric character  W      Any Non-alphanumeric character  m      m Repetitions  m n    m to n Repetitions         Zero or more repetitions         One or more repetitions         Optional character  s      Any Whitespace  S      Any Non-whitespace character           Starts and ends           Capture Group  a bc   Capture Sub-group         Capture all  ab cd  Matches ab or cd

[java] How do I use a delimiter with Scanner.useDelimiter in Java?

Examples related to java

Examples related to java.util.scanner

Examples related to delimiter