用逗号和空格分隔输入的字符串

Question

        while(scan.hasNext()){
        String line = scan.next();
        String[] tempArray = line.split(",\\s*");

        for (int i=0; i<3; i++){
            System.out.println(tempArray[i]);
        }

My input file looks like:

A, 0, 3 
C, 2, 2 
BB, 3, 3 
DA, -3, 0 
ED, 2, -2

It returns A, then gives me an error. What gives?

Answer 1

I would split on comma and then trim() the String ,

while(scan.hasNextLine()){                   // <-- hasNextLine()
  String line = scan.nextLine();             // <-- nextLine()
  String[] tempArray = line.split(",");      // <-- split on the comma.

  for (int i=0; i<tempArray.length; i++){    // <-- use the array length
    System.out.println(tempArray[i].trim()); // <-- trim() the String
  }
}

Answer 2

String line = scan.next();

For your input file, the first time you access this, line will be equal to "A," , which is not what you wanted.

This is because Scanner#next() only reads up until a whitespace character, which is present in the input file between A, and 0, . Hence, why only A, is returned.

Instead use

String line = scan.nextLine();

Which will read up until a line break. So the first loop will set line to "A, 0, 3" .

---

Debugging can really help improve programming abilities. Printing out the return of line to see what is being processed could have definitely helped with this. Being able to then figure out what is happening to produce those results is a lot easier.