如何在Java中也从包含字符串的文件中扫描整数

Question

How would I get my scanner stream to read just the integers in

Jane    354
Jill    546
Jenny   718
Penny   125

The Scanner method nextLine() read both the name, and the number, so I suppose I could just parse it out, but I wanted to know if there were a way for nextInt() to skip the name and only read the numbers because it fails right away when it sees that it starts with a String .

Answer 1

How about using next() , ignore its result and then use nextInt() ? This should do exactly what you need if all your lines are in format you presented in your question.

Answer 2

You can just call scanner.next() and do nothing with it to skip the string, for instance:

// Scanner sc;
while(sc.hasNextLine()){
    sc.next(); //Skip string
    int number = sc.nextInt();
}

Answer 3

You could also use scanner.nextLine() and then grab the int with a reg ex matcher

String mydata = scanner.nextLine();
Pattern pattern = Pattern.compile([0-9]+);
Matcher matcher = pattern.matcher(mydata);
if (matcher.find()){
    int num = Integer.parseInt(matcher.group(1));
}

Answer 4

You could do something like this

Scanner read = new Scanner(new File("some file here"));
while(read.hasNext()){
    if(read.next() instanceof Integer){
        System.out.println(read.next());
    }
}