Java Problem with ArrayLists

thomasjad

Hi,I'm making a program where i have a text file with a name and number on each line..is there a way to read the number into the arrayList as an int,or even later convert it to an int?

dlofnep

Is it a String on the first place? You could use Integer.parseInt(string);

thomasjad

well the text file looks like
john 15
bob -3
etc..
i dont know how long the text file will be,i want to read the numbers into an arraylist,and be able to add or subtract to them..

ronivek

http://java.sun.com/docs/books/tutorial/essential/io/

Should give you everything you need in terms of File IO and such. After that it should be pretty trivial to get your file into whatever data structure you're interested in.

If you want more specific help I would suggest posting some of your attempt code if you run into problems.

Civilian_Target

Check out the Java Scanner class, it's what you're looking for (you need to be in Java 6 land)

So you're looking for something like:

class DataPair{
    public int number;
    public String name;
}

....
Set<DataPair> pairs = new HashSet()<DataPair>;
while(scanner.hasNext()){
   <make new pair, read the ints using read int and the strings using read string, and add to the set>
}
...