Array

Defining Arrays

The Array object is used to store a set of values in a single variable name.

We define an Array object with the new keyword. The following code line defines an Array object called myArray:

var myArray=new Array()

There are two ways of adding values to an array (you can add as many values as you need to define as many variables you require).

1:

var mycars=new Array();
mycars[0]="Saab";
mycars[1]="Volvo";
mycars[2]="BMW";

You could also pass an integer argument to control the array's size:

var mycars=new Array(3);
mycars[0]="Saab";
mycars[1]="Volvo";
mycars[2]="BMW";

2:

var mycars=new Array("Saab","Volvo","BMW");

Note: If you specify numbers or true/false values inside the array then the type of variables will be numeric or Boolean instead of string.


Accessing Arrays

You can refer to a particular element in an array by referring to the name of the array and the index number. The index number starts at 0.

The following code line:

document.write(mycars[0]);

will result in the following output:

Saab


Modify Values in Existing Arrays

To modify a value in an existing array, just add a new value to the array with a specified index number:

mycars[0]="Opel";

Now, the following code line:

document.write(mycars[0]);

will result in the following output:

Opel

Array Object Methods

FF: Firefox, N: Netscape, IE: Internet Explorer

Method Description FF N IE
concat() Joins two or more arrays and returns the result 1 4 4
join() Puts all the elements of an array into a string. The elements are separated by a specified delimiter 1 3 4
pop() Removes and returns the last element of an array 1 4 5.5
push() Adds one or more elements to the end of an array and returns the new length 1 4 5.5
reverse() Reverses the order of the elements in an array 1 3 4
shift() Removes and returns the first element of an array 1 4 5.5
slice() Returns selected elements from an existing array 1 4 4
sort() Sorts the elements of an array 1 3 4
splice() Removes and adds new elements to an array 1 4 5.5
toSource() Represents the source code of an object 1 4 -
toString() Converts an array to a string and returns the result 1 3 4
unshift() Adds one or more elements to the beginning of an array and returns the new length 1 4 6
valueOf() Returns the primitive value of an Array object 1 2 4
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