Array Methods

Methods available on Array<T> types. Strata arrays are generic, meaning Array<Int> contains only integers. Using raw Array is equivalent to Array<Mixed>.

Modification

push

Adds an item to the end of the array and returns the new size.

fn push(item: T): Int

let numbers = [1, 2];
numbers.push(item: 3);
// numbers is [1, 2, 3]

pop

Removes and returns the last item from the array. Returns Null if empty.

fn pop(): T|Null

let stack = [1, 2];
let lastItem = stack.pop(); // 2
// stack is [1]

unshift

Adds an item to the beginning of the array and returns the new size.

fn unshift(item: T): Int

let queue = [2, 3];
queue.unshift(item: 1);
// queue is [1, 2, 3]

shift

Removes and returns the first item from the array. Returns Null if empty.

fn shift(): T|Null

let queue = [1, 2];
let firstItem = queue.shift(); // 1
// queue is [2]

Transformation

map

Creates a new array by applying a function to every element. The callback must have explicit parameter types. Note: The return type of the callback determines the type of the new array.

fn map<U>(callback: (T) -> U): Array<U>

let numbers = [1, 2, 3];
let doubledNumbers = numbers.map((num: Int) => num * 2);
// doubledNumbers is [2, 4, 6]

filter

Creates a new array with all elements that pass the test implemented by the provided function.

fn filter(callback: (T) -> Bool): Array<T>

let numbers = [1, 2, 3, 4];
let evenNumbers = numbers.filter((num: Int) => num % 2 == 0);
// evenNumbers is [2, 4]

reverse

Returns a new array with the elements in reverse order.

fn reverse(): Array<T>

let sequence = [1, 2, 3];
let reversedSequence = sequence.reverse(); // [3, 2, 1]

merge

Merges this array with another array, returning a new array.

fn merge(other: Array<T>): Array<T>

let firstBatch = [1, 2];
let secondBatch = [3, 4];
let combined = firstBatch.merge(secondBatch); // [1, 2, 3, 4]

Inspection

count

Returns the number of elements in the array.

fn count(): Int

let items = [1, 2, 3];
print(items.count()); // 3

contains

Checks if the array contains the specified item.

fn contains(item: T): Bool

let fruits = ["apple", "banana"];
if fruits.contains("apple") {
    print("Has apple");
}

join

Joins all elements of the array into a string, separated by glue.

fn join(glue: String): String

let words = ["hello", "world"];
print(words.join(glue: " ")); // "hello world"