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Array constructor

In JavaScript you create an array instance using the constructor Array.

Description

Declares an array that allows us to store collections of information that we may want to manipulate or use later.

An array can be created empty, with a length or with elements.

Syntax


Signature Description
var aArray = new Array();Create an empty array.
var bArray = new Array(arrayLength);Create an array with the specified length.
var cArray = new Array(element0, element1, ..., elementN);Create an array with specified elements.
var dArray = [element0, element1, ..., elementN];Shorthand array creation with specified elements.

Parameters


Parameter Description
arrayLengthA number between 0 and 4,294,967,295 where an array is created with that length:
  • Numbers outside this range throw a RangeError exception.
  • If the parameter is not a number a new array is created with a length of 1 with the parameter as the first elements value.
element0, element1, ..., elementNWhen two or more arguments are passed an array is created using the arguments passed as the elements of the array.

Class Properties


Class Property Description
prototypeEnables property assignment to objects of type Array.

Instance Properties


Instance Property Description
constructorReturns a reference to the Array function that created the prototype.
lengthA positive integer holding the number of elements within an array.

Class Methods

None.

Instance Methods

By using methods of the Array object we can also access elements of arrays, manipulate arrays after creation and even create new arrays from existing arrays.


Instance Method Description
Getter (Accessor) MethodsThese methods DO NOT modify the Array object
concat()Returns a new array composed of concatenated array(s) and/or value(s).
join()Creates a string from the elements within an array.
slice()Returns a new array comprising of a section of an existing array.
toString()Returns a string composed of concatenated array elements delimited by commas.
Setter (Mutator) MethodsThese methods DO modify the Array object
pop()Removes the last element of an array and returns that elements value to the caller.
push()Adds element(s) to the end of an array and returns the new length of the array.
reverse()Reverses the order of elements within an array.
shift()Removes the first element of an array and returns that elements value to the caller.
sort()sorts the elements within an array.
splice()adds and/or removes elements from within an array.
unshift()adds element(s) to the start of an array and returns the new length of the array.

Accessing Arrays

Arrays can be accessed by naming the array and stating the index for the item in the array you want to retrieve, just be aware that arrays are zero-indexed.

Examples




// Create an array with three elements.
var anArray = new Array('one', 'two', 'three');
alert(anArray + ' - ' + anArray.length);

// Create an array with a length of 10.
var newArrayWithLength = new Array(10);
alert(newArrayWithLength + ' - ' + newArrayWithLength.length);


Press the button below to action the above code:


The array literal syntax can also be used to create arrays by using square brackets [ ]. This method of array creation requires less typing and will be used in these tutorials from now on.



// Create an empty array.
var anEmptyArray = []

// Create an array with elements.
var weekendDays = ['Fri', 'Sat', 'Sun'];

// Create an array with mixed types of number, boolean and string.
var mixedTypeArraysAreFine = [1, true, 'Learn JavaScript'];
alert(anEmptyArray + ' - ' + weekendDays + ' - ' + mixedTypeArraysAreFine)


Press the button below to action the above code:


Related Tutorials

JavaScript Intermediate Tutorials - Lesson 1 - Arrays





  

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