List<T> stores elements in a specified order and provides indexed access to them. Indices start from zero – the index of the first element – and go to lastIndex which is the (list.size - 1).
```
val numbers = listOf("one", "two", "three", "four")
println("Number of elements: ${numbers.size}")
println("Third element: ${numbers.get(2)}")
println("Fourth element: ${numbers[3]}")
println("Index of element \"two\" ${numbers.indexOf("two")}")
```
List elements (including nulls) can duplicate: a list can contain any number of equal objects or occurrences of a single object. Two lists are considered equal if they have the same sizes and structurally equal elements at the same positions.
```
val bob = Person("Bob", 31)
val people = listOf(Person("Adam", 20), bob, bob)
val people2 = listOf(Person("Adam", 20), Person("Bob", 31), bob)
println(people == people2)
bob.age = 32
println(people == people2)
```
MutableList<T> is a List with list-specific write operations, for example, to add or remove an element at a specific position.
```
val numbers = mutableListOf(1, 2, 3, 4)
numbers.add(5)
numbers.removeAt(1)
numbers[0] = 0
numbers.shuffle()
println(numbers)
```
As you see, in some aspects lists are very similar to arrays. However, there is one important difference: an array's size is defined upon initialization and is never changed; in turn, a list doesn't have a predefined size; a list's size can be changed as a result of write operations: adding, updating, or removing elements.
In Kotlin, the default implementation of List is ArrayList which you can think of as a resizable array.