How to scan this line and use scan.skip()?

I have a .txt file with lines of this format example : torch ; 3.0 ; 23.0

I want to scan it in order to place the first item in a String, and the second and third in a float.

Here is what I have done so far but the scan.skip(" ; ") doesn't work, I have also tried scan.skip(Pattern.compile(" ; ") but it didn't work either.

File file = new File(dir);
    try {
        Scanner scan = new Scanner(file);
        scan.skip(" ; ");
        scan.useDelimiter(Pattern.compile(" ; "));
        while (scan.hasNextLine()) {
            String s = scan.next();
            float f1 = scan.nextFloat();
            float f2 = scan.nextFloat();
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

Do you have any solutions for me ?
Thanks

Don't change the delimiter of the Scanner you're using to read the File. Instead, instantiate an inner Scanner to parse the lines you read from the file. Aslo, I would use a try-with-Resources to make sure the Scanner (and File) are closed. Like,

File file = new File(dir);
try (Scanner scan = new Scanner(file)) {
	while (scan.hasNextLine()) {
		Scanner lineScan = new Scanner(scan.nextLine());
		lineScan.useDelimiter(Pattern.compile("\\s*;\\s*"));

		String s = lineScan.next();
		float f1 = lineScan.nextFloat();
		float f2 = lineScan.nextFloat();
		System.out.printf("%s %.2f %.2f%n", s, f1, f2);
	}
} catch (FileNotFoundException e) {
	e.printStackTrace();
}

You may use ; or \n as delimiter and no need to skip, also I'd suggest to use Float.parseFloat(scan.next());

Scanner scan = new Scanner(file);
scan.useDelimiter(Pattern.compile("[;\\n]"));
while (scan.hasNextLine()) {
    String s = scan.next();
    float f1 = Float.parseFloat(scan.next());
    float f2 = Float.parseFloat(scan.next());
    System.out.println(s + " " + f1 + " " + f2);
}

Answers provided here or here would solve your problem.

However, I want to explain why your code does not work, and how can you make it work.

Have a look at Scanner#skip(String pattern) documentation, which says, that:

>If a match to the specified pattern is not found at the current position, then no input is skipped and a NoSuchElementException is thrown.

So, your scan.skip(" ; "); blocks the thread, and keeps reading the tokens, until your input matches the specified pattern (;) to skip, or a NoSuchElementException is thrown.

If you want to use .skip(..), you can just change the order of your method calls, like:

try {
    Scanner scan = new Scanner(file);
    while (scan.hasNextLine()) {
        String s = scan.next();
        scan.skip(" ; ");
        float f1 = scan.nextFloat();
        scan.skip(" ; ");
        float f2 = scan.nextFloat();
    }
}