Read integers from txt file and storing into an ar

Question

I'm having issues reading and storing only integers from a text file. I'm using a int array so I want to do this without list. I'm getting a input mismatch exception, and I don't know how I should go about correcting that issue. The text files being read from also include strings.

  public static Integer[] readFileReturnIntegers(String filename) {
     Integer[] array = new Integer[1000];
     int i = 0;
    //connect to the file
     File file = new File(filename);
     Scanner inputFile = null;
     try {
        inputFile = new Scanner(file);
     } 
     //If file not found-error message
        catch (FileNotFoundException Exception) {
           System.out.println("File not found!");
        }
    //if connected, read file
     if(inputFile != null){         
        System.out.print("number of integers in file \"" 
              + filename + "\" = \n");
        //loop through file for integers and store in array     
        while (inputFile.hasNext()) {
           array[i] = inputFile.nextInt();
           i++;
        }
        inputFile.close();
     }
     return array;
  }

Answer 1

You might use something like this (to skip over any non-int(s)), and you should close your Scanner!

// if connected, read file
if (inputFile != null) {
  System.out.print("number of integers in file \""
      + filename + "\" = \n");
  // loop through file for integers and store in array
  try {
    while (inputFile.hasNext()) {
      if (inputFile.hasNextInt()) {
        array[i] = inputFile.nextInt();
        i++;
      } else {
        inputFile.next();
      }
    }
  } finally {
    inputFile.close();
  }
  // I think you wanted to print it.
  System.out.println(i);
  for (int v = 0; v < i; v++) {
    System.out.printf("array[%d] = %d\n", v, array[v]);
  }
}

Answer 2

What you need to do is before you get a new value and try to put it into the array you need to check to make sure that it is in fact an int and if it isn't then skip over it and move on to the next value. Alternately you could make a string array of all of the values and then copy only the integers into a separate array. However, the first solution is probably the better of the two.

Also... As has been mentioned in the comments it tends to be easier to read the integers in as strings and then parse the values from them...

Answer 3

Change hasNext() to hasNextInt() in your while loop.