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Methods

Modifying Elements

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> order = new ArrayList<String>();
        order.add("Whopper");
        order.add("Chicken Nugget");
        order.add("Fries");
        order.set(1, "Coke");
        // This sets the first element (chicken nuggets) to a coke instead
    }
}

Using set(), you can set the element at the index number to a new element.

Removing Elements

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> order = new ArrayList<String>();
        order.add("Whopper");
        order.add("Chicken Nugget");
        order.add("Fries");
        order.remove(2);
        // Removes Fries from the ArrayList
    }
}

Similar to set(), the remove() method removes an element at an index number.

Getting the Size of an ArrayList

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> order = new ArrayList<String>();
        order.add("Whopper");
        order.add("Chicken Nugget");
        order.add("Fries");
        System.out.println(order.size());
        // Outputs the size of the ArrayList, in this case: 3
    }
}

size() returns the size of the ArrayList.

Iterating Over Elements

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> order = new ArrayList<String>();
        order.add("Whopper");
        order.add("Chicken Nugget");
        order.add("Fries");
        for (int i = 0; i < order.size(); i++) {
            System.out.println(order.get(i));
        }
        // Outputs:
        // Whopper
        // Chicken Nugget
        // Fries
    }
}

By using a combination of the for loop and the get method, we can iterate through the ArrayList and print out each element at every index.