JS Arrays

js-arrays.md

Arrays

Arrays are data structures with automatically indexed positions. Array indices are zero–based.

Creating arrays

Literal notation

JSLint suggests literal notation for creating arrays and objects. Allows for initializing values.

var someArray = [1, 2, 3];

Constructor

var someArray = new Array();
  someArray[0] = 1;
  someArray[1] = 2;
  someArray[2] = 3;

Some array methods

shift() removes cell at first position and retrieves it's value.

pop() removes cell at last position and retrieves it's value.

push() adds a cell in the last postion nad enters a value.

arrayData[7] = undefined; Use undefined to create empty cells.

Join and Split

join() turns an array into a string.

split() turns a string into an array.

var fruits = ["Lemon","Apple","Orange","Peach"];

var str = fruits.join(', ');

alert(str); // "Lemon, Apple, Orange, Peach"

var fruits = "Apple,Orange,Peach";

var arr = fruits.split(',');

// arr is ["Apple", "Orange", "Peach"]

alert(arr[0]);