Arrays

In Kotlin, we can create an array by using the arrayOf() library function:

    val array = arrayOf(1, 2, 3)

Alternatively, we can create Array from an initial size and a function, which are used to generate each element:

    val perfectSquares = Array(10, { k -> k * k }) 

Unlike Java, arrays are not treated as special by the language, and are a regular collection classes. Instances of arrays provide an iterator function and a size function, as well as a get and a set function. The get and set functions are also available through bracket syntax, like many C-style languages:

    // Pull the first and second array value into variables
    val element1 = array[0]
    val element2 = array[1] 
    // Set the second array item value to 5
    array[2] = 5 

To avoid boxing types that will ultimately be represented as primitives in the JVM, Kotlin provides alternative array classes that are specialized for each of the primitive types. This allows performance-critical code to use arrays as efficiently as they would do in plain Java. The provided classes are ByteArray, CharArray, ShortArray, IntArray, LongArray, BooleanArray, FloatArray, and DoubleArray.