Help summing a arraylist

Question

Currently the code below will give me a line by line listing of the values, if i wanted to sum the values for one total, can someone give me an example of going about doing this?

if (value != null && !value.isEmpty()) {
    Set set = value.keySet();
    Object[] key = set.toArray();
    Arrays.sort(key);
    // System.out.println("test" + Arrays.asList(key));

    for (int i = 0; i < key.length; i++) {
        // System.out.println(value.get((String)key[i]))
        ArrayList list = (ArrayList) value.get((String) key[i]);

        if (list != null && !list.isEmpty()) {
            Iterator iter = list.iterator();
            double itemValue = 0;

            while (iter.hasNext()) {
                Iemunbuf p = (Itemunbuf) iter.next();

                if (p != null) {
                    propertyValue = itemValue + p.getitemValue().doubleValue();
                    System.out.println(itemValue);
                }

                // buf2.append(NL);
                buf2.append(t1 + "\t");
                // System.out.println(t1);
                buf2.append(NL);
            }

            buf1.append(NL);
            double amount = itemValue;
            buf1.append("  " + money.format(amount) + "  ");
        }
    }
}

This is not your actual code. This code doesn't even compile, and when the obvious errors are fixed, it doesn't do what you imply it does. Why not show us your actual code? — Tom Anderson
– Tom Anderson, Commented Sep 13, 2010 at 16:53

Erick Robertson · Accepted Answer · 2010-09-13 15:50:01Z

2

Above the for loop loop, put:

double totalAmount = 0.0;

Inside the for loop, right after the double amount = itemValue line, put:

totalAmount += amount;

answered Sep 13, 2010 at 15:50

Erick Robertson

33.1k13 gold badges73 silver badges98 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user442471 Over a year ago

It is totalling, however, i want only want the final total. Results below. this 500000.0 1000000.0 this 1500000.0 100000.0 this 1600000.0 30000.0 this 1630000.0 40000.0 this 1670000.0 200000.0 this 1870000.0 250000.0 this 2120000.0

Erick Robertson Over a year ago

So only record it outside of the for loop. Don't add the totalAmount to the buffer until after the for loop closes.

BigMac66 · Accepted Answer · 2010-09-13 16:45:16Z

1

Don't know why you assign a value to amount just to print it - I suspect that what you mean to do was use amount as a grand total. Well it won't work the way you have written as amount is declared inside your loop and so will always be initialized to 0.0 before you make the assignment - that and it is a flat out assignment and not summation. Declare amount outside the loop like Erick suggested then say amount += itemValue.

Hope I understood your question properly.

answered Sep 13, 2010 at 16:45

BigMac66

1,5586 gold badges20 silver badges36 bronze badges

Comments

Jon Freedman · Accepted Answer · 2010-09-13 16:36:30Z

0

Judging by the code you posted your value variable has the type Map<String, ArrayList<Itemunbuf>> but as you aren't making use of any generic types you may want to read up on that first (Sun tutorial).

You can simplify your code to the following

if (value != null) {
    for (ArrayList<Itemunbuf> list : value.getValues()) {
        if (list != null) {
            for (Itemunbuf p : list) {
                if (p != null) {
                    // do stuff
                }
            }
        }
    }
}

If you define your totalAmount variable outside the scope of this code and increment it where I have the // do stuff comment you will get the sum of all the Itemunbuf objects contained in your values Map

answered Sep 13, 2010 at 16:36

Jon Freedman

9,7176 gold badges43 silver badges59 bronze badges

Collectives™ on Stack Overflow

Help summing a arraylist

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related