sc = new Scanner(new File(dataFile));
sc.useDelimiter(",|\r\n");
I don't understand how delimiter works, can someone explain this in layman terms?
The scanner can also use delimiters other than whitespace.
Easy example from Scanner API:
String input = "1 fish 2 fish red fish blue fish";
// \\s* means 0 or more repetitions of any whitespace character
// fish is the pattern to find
Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*");
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.
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