JavaScript Array Object
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Create an array Create an array, assign values to it, and write the values to the output.
(You can find more examples at the bottom of this page)
Complete Array Object Reference
For a complete reference of all the properties and methods that can be used with the Array object, go to our complete Array object reference.
The reference contains a brief description and examples of use for each property and method!
What is an Array?
An array is a special variable, which can hold more than one value, at a time.
If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:
var car1=”Saab”;var car2=”Volvo”;var car3=”BMW”; |
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However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300?
The best solution here is to use an array!
An array can hold all your variable values under a single name. And you can access the values by referring to the array name.
Each element in the array has its own ID so that it can be easily accessed.
Create an Array
An array can be defined in three ways.
The following code creates an Array object called myCars:
1:
var myCars=new Array(); // regular array (add an optional integermyCars[0]=”Saab”; // argument to control array’s size)myCars[1]=”Volvo”;myCars[2]=”BMW”; |
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2:
var myCars=new Array(“Saab”,”Volvo”,”BMW”); // condensed array |
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3:
var myCars=[“Saab”,”Volvo”,”BMW”]; // literal array |
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Note: If you specify numbers or true/false values inside the array then the variable type will be Number or Boolean, instead of String.
Access an Array
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]); |
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will result in the following output:
Saab |
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Modify Values in an Array
To modify a value in an existing array, just add a new value to the array with a specified index number:
myCars[0]=”Opel”; |
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Now, the following code line:
document.write(myCars[0]); |
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will result in the following output:
Opel |
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The Array object is used to store multiple values in a single variable.
For a tutorial about Arrays, read our JavaScript Array Object tutorial.
Array Object Properties
Property | Description |
|---|---|
constructor | Returns the function that created the Array object’s prototype |
length | Sets or returns the number of elements in an array |
prototype | Allows you to add properties and methods to an object |
Array Object Methods
Method | Description |
|---|---|
concat() | Joins two or more arrays, and returns a copy of the joined arrays |
indexOf() | |
join() | Joins all elements of an array into a string |
pop() | Removes the last element of an array, and returns that element |
push() | Adds new elements to the end of an array, and returns the new length |
reverse() | Reverses the order of the elements in an array |
shift() | Removes the first element of an array, and returns that element |
slice() | Selects a part of an array, and returns the new array |
sort() | Sorts the elements of an array |
splice() | Adds/Removes elements from an array |
toString() | Converts an array to a string, and returns the result |
unshift() | Adds new elements to the beginning of an array, and returns the new length |
valueOf() | Returns the primitive value of an array |
splice() Method
Definition and Usage
The splice() method adds and/or removes elements to/from an array, and returns the removed element(s).
Note: This method changes the original array!
Syntax
array.splice(index,howmany,element1,…..,elementX) |
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Parameter | Description |
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index | Required. An integer that specifies at what position to add/remove elements |
howmany | Required. The number of elements to be removed. If set to 0, no elements will be removed |
element1, …, elementX | Optional. The new element(s) to be added to the array |
Browser Support
The splice() method is supported in all major browsers.
Examples
Example 1 Add an element to position 2 in the array: <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,0,”Lemon”) + “<br />”);document.write(fruits); </script>The output of the code above will be: Removed:Banana,Orange,Lemon,Apple,Mango Try it yourself » | <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,0,”Lemon”) + “<br />”);document.write(fruits); </script> | Removed:Banana,Orange,Lemon,Apple,Mango |
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<script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,0,”Lemon”) + “<br />”);document.write(fruits); </script> | ||
Removed:Banana,Orange,Lemon,Apple,Mango |
Example 2 Remove one element from position 2, and add a new element to position 2 in the array: <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,1,”Lemon”) + “<br />”);document.write(fruits); </script>The output of the code above will be: Removed: AppleBanana,Orange,Lemon,Mango Try it yourself » | <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,1,”Lemon”) + “<br />”);document.write(fruits); </script> | Removed: AppleBanana,Orange,Lemon,Mango |
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<script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,1,”Lemon”) + “<br />”);document.write(fruits); </script> | ||
Removed: AppleBanana,Orange,Lemon,Mango |
Example 3 Remove two elements, start from position 2, and add a new element to position 2 in the array: <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,2,”Lemon”) + “<br />”);document.write(fruits); </script>The output of the code above will be: Removed: Apple,MangoBanana,Orange,Lemon Try it yourself » | <script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,2,”Lemon”) + “<br />”);document.write(fruits); </script> | Removed: Apple,MangoBanana,Orange,Lemon |
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<script type=”text/javascript”> var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];document.write(“Removed: ” + fruits.splice(2,2,”Lemon”) + “<br />”);document.write(fruits); </script> | ||
Removed: Apple,MangoBanana,Orange,Lemon |
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