add and get

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.

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).

From the list below, take the first and last element with get; print each on its own line.

Show example solution

System.out.println(fruits.get(0));
System.out.println(fruits.get(fruits.size() - 1));

Fill in the blank: get the first element

ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
String first = fruits.____(0);

Show answer

ArrayList<String> fruits = new ArrayList<>();
fruits.add("Elma");
String first = fruits.get(0);

Next lesson: HashMap