Scanner.useDelimiter not working as expected

Question

The actual answer is supposed to be stack and overflow in two separate lines for input stack.overflow; delimiter used is ".". Nothing is shown in the output:

Scanner p = new Scanner(System.in);

p.useDelimiter(".");

System.out.println("delimiter is "+ p.delimiter());

\\this above line is producing expected output

while(p.hasNext()){
    System.out.println(p.next());
}

For input stack.overflow and delimiter "." expected output is

stack
overflow

`System.in` always `hasNext()` unless you close it. You can always type more. — TiiJ7, Jan 24 '19 at 07:41
Nope. `useDelimiter` accepts a regular expression. Look that up. — Sweeper, Jan 24 '19 at 07:42

BackSlash · Accepted Answer · 2019-01-24T07:50:38.933

4

p.useDelimiter(".");

Delimiter is a regex, and . in regex means "every possible character". You are using "every possible character" as delimiter, making Scanner return everything between each pair of characters, which will result in a lot of empty strings.

Escape the dot instead:

p.useDelimiter("\\.");

Output:

delimiter is \.
stack
overflow

edited Jan 24 '19 at 07:50

answered Jan 24 '19 at 07:40

BackSlash

21,927
22
96
136

i deleted my answer this was correct thanks Stultuske for pointing out my error. – Fractal Jan 24 '19 at 07:51

Scanner.useDelimiter not working as expected

1 Answers1