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up vote -1 down vote favorite

It is necessary that I create a String[] with 5 strings, each of these strings carries multiple substrings with data separated by commas, I must convert this array of int into ArrayList to section the sub strings in this order: the numbers '1, 2, 3, 4, 5' are student ID numbers. 'john, suzan, jack, erin, adan' are first names, etc.. However, the only issue I ran into is when I'm trying to print the array of grades, ex: '88, 79, 59' into an ArrayList object that prints: 887959(1 arraylist object), NOT 88 (1 arraylist object), 79(another arraylist object),...

What am I doing wrong? How do I fix this?

Code:

String[] kaizer = 
        {

            "1,John,Smith,[email protected],20,88,79,59",
            "2,Suzan,Erickson,Erickson_1990@gmailcom,19,91,72,85",
            "3,Jack,Napoli,The_lawyer99yahoo.com,19,85,84,87",
            "4,Erin,Black,[email protected],22,91,98,82",
            "5,Adan,Ramirez,[email protected],23,100,100,100"
        };
ArrayList<Integer> grades = new ArrayList<Integer>(); 
for (int i = 0; i < kaizer.length; i++) {
    String s = kaizer[i]; //volatile reference
    String[] parts = s.split(","); 
    //volatile reference
    String id = parts[0];
    String name = parts[1];
    String lastname = parts[2];
    String email = parts[3];
    String age = parts[4];
    grades.add(Integer.parseInt(parts[5])); 
    grades.add(Integer.parseInt(parts[6]));
    grades.add(Integer.parseInt(parts[7]));
    //Widget w = new Widget(id, name, num);
    //mywidgets.add(w);
}

This is supposed to print the set of substrings like this:

887959 
917285
858487
919882
100100100

System.out.println(grades.get(0)); 
System.out.println(grades.get(1));
System.out.println(grades.get(2));
System.out.println(grades.get(3));
System.out.println(grades.get(4));

Instead... it prints:

8879599172

The problem lies in the output: '8879599172'

share|improve this question
    
Since you're working with Java, I think you should try to solve this problem using OOP. – Luiggi Mendoza Aug 31 '15 at 14:28
    
You need 1 grades array per for loop. Maybe a hashmap<int, ArrayList<Integer>>, where the key is id and value the grades for this id. – Danilo Silva Aug 31 '15 at 14:29
1  
@DaniloSilva or just use a List<Student> where the Student data is obtained after parsing each String. – Luiggi Mendoza Aug 31 '15 at 14:30
    
@LuiggiMendoza - Unfortunately OP might not know what it means. Many courses teach procedural programming in Java, sometimes using main() as the only method. – PM 77-1 Aug 31 '15 at 14:31
    
@LuiggiMendoza Yes, I think this is the better solution – Danilo Silva Aug 31 '15 at 14:31
up vote 1 down vote

grades is an ArrayList and as far as it's concerned you are just adding Integers to it. It doesn't know when it's supposed to break. Index 3 is just the Integer after index 2. If you want to combine each one into combined values you can do grades.add(Integer.parseInt(parts[5]+parts[6]+parts[7])) or you can insert a line break after each 3 values added to grades. You can also make a grades a List with sublists that are each a List of type Integer.

share|improve this answer
    
BINGO! you got it! in just a few minutes you saved me from killing myself, gj! – Adan Ramirez Aug 31 '15 at 14:30
up vote 0 down vote

You are storing all the values in a 1-dimensional ArrayList, in your scenario, you should consider using a 2-dimensional ArrayList.

ArrayList<ArrayList<Integer>> grades = new ArrayList<ArrayList<Integer>>(); 
for (int i = 0; i < kaizer.length; i++) {
    String s = kaizer[i]; //volatile reference
    String[] parts = s.split(","); 
    //volatile reference
    String id = parts[0];
    String name = parts[1];
    String lastname = parts[2];
    String email = parts[3];
    String age = parts[4];

    ArrayList<Integer> subList = new ArrayList<Integer>();
    subList.add(Integer.parseInt(parts[5])); 
    subList.add(Integer.parseInt(parts[6]));
    subList.add(Integer.parseInt(parts[7]));
    grades.add(i, subList);

    //Widget w = new Widget(id, name, num);
    //mywidgets.add(w);
}

Then, you can loop through the grades for each student:

//for each student
for(ArrayList<Integer> list : grades)
{
    for(int grade : list)
    {
        //do something with each grade
    }
}
share|improve this answer

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