为arraylist中的每个项目分配值

Question

I have an arraylist with integers that represent a person. I want to assign every 4th person a tablenumber, but there are more then 4 people in that arraylist, so I want to

• assign the next 4 people to a different table, and the
• 4 people after that to a new table

How can I do that?

This is what I've tried so far:

    try {
        String[] toernooi = toernooien2.getSelectedItem().toString().split(" ");

        PreparedStatement stat = con.prepareStatement("SELECT speler FROM fullhouse.inschrijving_toernooi WHERE IT_betaaldatum is not null AND toernooi = ?;");
        stat.setString(1, toernooi[0]);
        ResultSet resultaat = stat.executeQuery();
        ArrayList<Integer> array = new ArrayList<>();

        PreparedStatement stat2 = con.prepareStatement("INSERT INTO fullhouse.indeling (person,tablenumber,ronde) VALUES (?,?,?)");

        for (int i = 1; resultaat.next(); i++) {
            stat2.setInt(1, resultaat.getInt(1));
            array.add(resultaat.getInt(1));
            stat2.execute();

            for (Integer arrayitem : array) 
            {

            }

        }

Answer 1

have a counter and check the counter while iterating and on 4th iteration revert back the counter to 1 and assign to a new table.

int counter=1;
for(Person p: list){
if(counter==4) {
//assing to a different table
counter=1;
continue;
}
//assign to an normal table
counter++;

}

Answer 2

You could use integer division to avoid having to worry about other variables or resetting. I have replaced the iterator with a normal loop because it seems more elegant to use a loop variable if we are having a counter to count up the List anyway:

private List<Integer> assign (List<Integer> guestList) {

    int size = guestList.size();

    for (int i = 0; i < size; i++) {

        guestList.add(i, i/4);

    }
        return guestList;
}

Assumptions:

• The .size() method gets the number of guests
• The first table number should be zero
• The size of the input List will not be out of range of integer division

This is my first answer - comments are appreciated :)

Answer 3

You should keep a counter of some kind in the for loop. When that counter has reached 4, you should reset it and change what is happening, accordingly. Rinse and repeat. Some of the finer implementation details I've left to you, as it's hard to tell exactly how you are doing and managing some things.

int counter = 0;
for (Integer arrayitem : array) 
    {
            counter++;
            assign to table;
            if (counter == 4)
            {
                change what table we are now assigning to;
                counter = 0;
            }
    }