add and get
- Java course
- Beginner
- Lesson 66/116
- 4 min
Learn collection operations with add() and get().
Adding and reading: add and get
You use add to put an element into an ArrayList and get to read one. get takes a zero-based index.
ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
fruits.add("Armut");
String first = fruits.get(0);
// first = "Elma"If the index is out of range, IndexOutOfBoundsException is thrown. That is why checking with size before calling get is safer.
Iterating the list with a loop
A for-each loop is very handy for walking the list. The String type appears in the loop variable; elements come one by one.
for (String name : names) {
System.out.println(name);
}You can also use the classic for (int i = 0; i < list.size(); i++) form; this is essential when you need the index (for example to call set).
Practice Print the first and last apple
From the list below, take the first and last element with get; print each on its own line.
Starter code
import java.util.ArrayList;
public class Main {
public static void main(String[] args) {
ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
fruits.add("Armut");
fruits.add("Muz");
// Print the first element
// Print the last element (size - 1)
}
}Sample solution
System.out.println(fruits.get(0));
System.out.println(fruits.get(fruits.size() - 1));Expected output
Elma Muz
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match call to result
| Term | Meaning |
|---|---|
add("X") |
Appends X at the end |
get(0) |
Returns the first element |
size() |
Returns the element count |
remove(0) |
Removes the first element |
2 Fill in the blank: get the first element
ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
String first = fruits.____(0);ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
String first = fruits.get(0);Explanation: get(0) returns the first element.
3 What does fruits.get(5) do when size is 3?
- It throws IndexOutOfBoundsException
- It returns the last element
- It returns null Correct answer
- It adds 5 elements to the list
Explanation: An invalid index throws an exception.