I'm trying to extract the numbers individual lines from a text file and perform an operation on them and print them to a new text file.
my text file reads somethings like
10 2 5 2
10 2 5 3
etc...
Id like to do some serious math so Id like to be able to call upon each number from the line I'm working with and put it into a calculation.
It seems like an array would be the best thing to use for this, but to get the numbers into an array do I have to use a string tokenizer?
Scanner sc = new Scanner(new File("mynums.txt"));
while(sc.hasNextLine()) {
String[] numstrs = sc.nextLine().split("\\s+"); // split by white space
int[] nums = new int[numstrs.length];
for(int i = 0; i < nums.length; i++) nums[i] = Integer.parseInt(numstrs[i]);
// now you can manipulate the numbers in nums[]
}
Obviously you don't have to use an int[] nums. You can instead do
int x = Integer.parseInt(numstrs[0]);
int m = Integer.parseInt(numstrs[1]);
int b = Integer.parseInt(numstrs[2]);
int y = m*x + b; // or something? :-)
Alternatively, if you know the structure ahead of time to be all ints, you could do something like this:
List<Integer> ints = new ArrayList<Integer>();
Scanner sc = new Scanner(new File("mynums.txt"));
while(sc.hasNextInt()) {
ints.add(sc.nextInt());
}
It creates Integer objects which is less desirable, but isn't significantly expensive these days. You can always convert it to an int[] after you slurp them in.
int y = m*x + b; sounds like some serious math to me just like the OP wanted :)
java.util.StringTokenizerhas been replaced withString.split(String). It's easier to use and makes your code a whole lot cleaner.