An array is an indexed, fixed-size sequence whose elements share a specified type. Kotlin provides arrays for cases where Java interoperability or performance makes them appropriate, while collections are generally preferred by default. section 8.0 section 8.3
Read command-line arguments
fun main(args: Array<String>) { for (i in args.indices) { println("Argument $i is: ${args[i]}") } } `Array<String>` declares an array of strings. `indices` supplies its valid indexes, and bracket syntax reads the element at each index.
Create and use arrays in several practical ways:
- `arrayOf("a", "b")` creates an array from supplied elements; `arrayOfNulls<String>(size)` creates a nullable array filled with nulls. section 8.2.5
- Use specialized primitive arrays such as `IntArray(5)` or `intArrayOf(0, 0, 0, 0, 0)` when the elements are integers. section 8.2.5
- Convert a collection with `toTypedArray()` when passing it to a Java array parameter or a Kotlin `vararg` parameter, using the spread operator at the call site. section 8.2.5
Although `Array<Int>` looks generic, its elements are boxed integers on the JVM (`java.lang.Integer[]`). Primitive arrays such as `IntArray` use specialized representations. Kotlin arrays compile to Java arrays, supporting interoperability while retaining Kotlin array syntax. section 8.2.5 section 8.3
