Array Object
There are three ways of defining an array:
var myfriends=new Array() //1) regular array. Pass an
optional integer argument
to control array's size.
myfriends[0]="John"
myfriends[1]="Bob"
myfriends[2]="Sue"
var myfriends=new Array("John", "Bob", "Sue") //2) condensed array
var myfriends=["John", "Bob", "Sue"] //3) literal array
Properties
| Properties |
Description |
| length |
A read/write property indicating the
current number of elements within the array. You may set this
property to dynamically expand an array's length. |
| prototype |
Use this property to attach additional
properties and/or methods that get reflected in all instances of the
array. |
Methods
Note:
"[]" surrounding a parameter below means the parameter is optional.
| Methods |
Description |
| concat(value1, ...) |
Concatenates all the argument values to the existing array, and
returns the new array. Values can be another array. Example(s). |
| join([separator]) |
Converts each element within the array to a string, and joins them
into one large string. Pass in an optional separator as argument to
be used to separate each array element. If none is passed, the
default comma (') is used. Example(s). |
| pop() |
Deletes the last element
within array and returns the deleted element. Original array is
modified. |
| push(value1, ...) |
Adds
the argument values to the end of the array, and modifies the
original array with the new additions. Returns the new length of the
array. |
| reverse() |
Reverses the order of all
elements within the array. Original array is modified. |
| shift() |
Deletes and returns the
first element within the array. Original array is modified to
account for the missing element (so 2nd element now becomes the
first etc). |
| slice(start, [end]) |
Returns
a "slice" of the original array based on the start and end
arguments. The slice includes the new array referenced by the start
index and up to but NOT including the end index itself. If "end" is
not specified, the end of the array is assumed. |
| splice(startIndex,
[how_many], [value1, ...]) |
Deletes how_many array elements
starting from startIndex, and replaces them with value1, value2 etc.
Returns the elements deleted from array. Example(s). |
| sort([SortFunction]) |
Sorts an array alphabetically and
ascending. By passing in an optional SortFunction, you may sort
numerically and by other criteria as well. Example(s). |
| toSource() |
Returns an array literal
representing the specified array. |
| toString() |
Returns a string
representing the array and its elements. |
| unshift(value1, ...) |
Adds
the argument values to the beginning of the array, pushing existing
arrays back. Returns the new length of the array. Original array is
modified. |
| valueOf() |
Returns the primitive
value of the array. |
Examples
concat(value1,
...)
var fruits=["Apple", "Oranges"]
var meat=["Pork", "Chicken"]
var result1=fruits.concat(meat) //creates ["Apple", "Oranges", "Pork",
"Chicken"]
var result2=result1.concat(1, 2, 3) //creates ["Apple", "Oranges", "Pork",
"Chicken", 1, 2, 3]
join([separator])
var fruits=["Apple", "Oranges"]
var result1=fruits.join() //creates the String "Apple,Oranges"
var result2=fruits.join("*") //creates the String "Apple*Oranges"
sort([SortFunction])
var myarray=["Bob","Bully","Amy"]
myarray.sort() //Array now becomes ["Amy", "Bob", "Bully"]
var myarray2=[7, 40]
myarray2.sort() //Array now becomes [40, 7] since alphabetically, 40 proceeds 7.
For more info on sort(), including sorting an array in numerical order, see
this tutorial.
splice(startIndex,
[how_many], [value1, ...])
Splice() is one of those array functions that can use some explanation. Lets
look at its parameters in detail:
1) startIndex- the array element to begin the insertion or deletion of the
array.
2) how_many- the number of elements, beginning with the element specified in
startIndex, to delete from the array. Optional. Not specifying this parameter
causes all elements starting from startIndex to be deleted.
3) value1, value2 etc- Optional values to be inserted into the array, starting
at startIndex.
var myarray=[13, 36, 25, 52, 83]
myarray.splice(2, 2) //myarray is now [13, 36 , 83]. The 3rd and 4th element is
removed.
var myarray=[13, 36, 25, 52, 83] //reset array for 2nd example
myarray.splice(2, 3, 42, 15) //myarray is now [13, 36 , 42, 15]. The 3rd, 4th
and 5th element is removed, replaced with 42 and 15.
