Syntax
var variablename = new Array()
var variablename = new Array(int)
var variablename = new Array(arg1, ... , argN)
Arguments and Return Values Associated with the Array Object
| Arguments |
| int |
When the array constructor contains one argument, an array is created, and its length property is set to the value int. |
| arg1, ..., argN |
When the parameter list of the array constructor contains more than one argument, an array is created and the array is populated with the arguments. The array length property is set to the number of arguments in the parameter list. |
| Returns |
| |
The newly created array is returned from the constructor. |
Example
<html>
<script language="javascript">
<!--
myArray = new Array(10, 5, 22, 26, 12);
document.write("Item1=",myArray[0],"<br>");
document.write("Item3=",myArray[2],"<br>");
document.write("Item4=",myArray[3],"<br>");
//-->
</script>
</html>
Properties and Methods Used by the Array Object
| Property |
| length |
The number elements in the array |
| Methods |
| concat() |
Concatenates an array in the array |
| join() |
Concatenates all elements of an array into one string |
| pop() |
Deletes the last element from an array |
| push() |
Adds elements to the end of an array |
| reverse() |
Reverses the order of the elements in the array |
| shift() |
Deletes elements from the front of an array |
| slice() |
Returns a subsection of the array |
| sort() |
Sorts elements in array |
| splice() |
Inserts and removes elements from an array |
| toSource() |
Converts elements to a string with square brackets |
| toString() |
Converts elements to a string |
| unshift() |
Adds elements to the front of an array |
Array.concat()
Syntax
array.concat(arg1,...,argN)
Description
The concat() method adds the elements listed in the parameter list to the end of the existing array and returns the result. The original is not changed by this method. Should any of the arguments be Array, the elements of that array are concatenated to the array that called the method.
Example
myArray1 = new Array("red", "orange");
myArray2 = new Array("green", "yellow");
myArray3 = myArray1.concat(myArray2);
Array.join()
Syntax
array.join()
array.join(string)
Description
The join() method converts all the elements of the array to strings and then concatenates all the strings into one string. If an argument is provided in the parameter list, it is used to separate the elements in the string returned by the method.
Example
myArray1 = new Array("red", "orange", "purple");
result = myArray1.join("-");
Array.length
Syntax
array.length
Description
The length property holds the number of elements in the array. This property is a read/write variable. If the length property is overwritten with a number that is larger than the original, new elements are added to the end of the array and assigned undefined values. If the length property is overwritten with a number that is smaller than the original number, elements at the end of the array are lost.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
length1 = myArray1.length;
myArray1.length = 3;
Array.pop()
Syntax
array.pop()
Description
The pop() method pops elements off the end of the array by deleting the last element of the array and setting the array's length property to one less than its current value. This last element is returned from the method.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
thisColor = myArray1.pop();
document.write(thisColor," was removed from array");
Array.prototype
Syntax
Array.prototype.property
Array.prototype.method
Description
The prototype property allows you to add new properties and methods to the Array object that can be used throughout your code
Example
Suppose that pop() method is available to some browsers but not support by Internet Explorer. To make this method available to all browsers, a new pop() method is created. This method overrides the functionality of the browser that is supported.
function pop(){
if(this.length != 0){
var lastElement = this[this.length-1];
this.length = this.length-1;
return lastElement;
}
}
Array.prototype.pop = pop;
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
var removeElement = myArray1.pop();
document.write(removeElement," was removed from the array");
Array.push()
Syntax
array.push(arg1,...,argN)
Description
The push() method pushes the elements specified in the parameter list on to the end of the array in the order they were listed. The value return is the last element that has been added to the end of the array, which is also the last argument in the parameter list.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
lastItem = myArray1.push("black", "white");
document.write("myArray contains ",myArray1.join(','))
Array.reverse()
Syntax
array.reverse()
Description
The reverse() method reverses the order of the elements in the array according to the array index numbers.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
myArray1.reverse();
document.write("Item1=",myArray1[0],"<br>");
document.write("Item3=",myArray1[2],"<br>");
document.write("Item4=",myArray1[3],"<br>");
Array.shift()
Syntax
array.shift()
Description
The shift() method deletes and returns the first element of the array. Once deleted, all the remaining elements are shifted down one spot, so the first position is filled by the element that was previously in the second position.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
aColor = myArray1.shift();
Array.slice()
Syntax
array.slice(start)
array.slice(start, stop)
Description
The slice() method returns a new array that contains the elements of the original array starting at position start and ending at the element position before stop. If no stop position is specified, the new array will contain the elements of the original array, starting at the position stated in start through the end of the array.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
myNewArray = myArray1.slice(1, 4);
Array.sort()
Syntax
array.sort()
array.sort(function)
Description
The sort() method rearrange the elements of the array based on a sorting order. If the method has no parameters, JavaScript attempts to convert all the elements of the array to strings and then sort them alphabetically. If the array should be sorted some other way, a function must be provided to handle the new sorting algorithm. The function specified must operate based on the following rules:
- The function must accept two arguments that are to be compared.
- The function must return a number indicating the order of the two arguments in relation to each other.
- If the first argument should appear before the second argument, a number less than zero should be returned from the function.
- If the first argument should appear after the second argument, a number greater than zero should be returned from the function.
- If both arguments are equivalent, zero should be returned from the function.
When the function specified by the sort() method returns zero, signifying that the arguments are equal, the arguments remain in the same order relative to each other after the function has been called.
Example
function mySort(arg1, arg2){
if(arg1.length < arg2.length)
return -1;
if(arg1.length > arg2.length)
return 1;
if(arg1.length == arg2.length)
return 0;
}
myArray1 = new Array("purple", "white", "red");
myArray1.sort(mySort);
Array.splice()
Syntax
array.slice(start, delete, arg3, ..., argN)
Description
The splice() method provides a way for elements to be either added to or deleted from the array. When the delete parameter contains a number other than zero, the elements beginning at start and ending at index start+ending are deleted from the array. If delete is zero, no elements are deleted. All elements from start to the end of the array are deleted when delete is not specified. If arguments follow the delete parameter, they are added to the array as elements beginning at the position specified by start. Existing elements are shifted up to allow room for the new elements.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
myArray1.splice(0, 1, "pink");
Array.toSource()
Syntax
array.toSource()
Description
The toSource() method returns one string representing the source of the Array object. The string that is returned contains all the elements in the array separated with commas. The entire string is enclosed with brackets ([]) to show it is an array. If another array is contained within an array, its contents are also part of the string with its own set of brackets.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
myArray2 = new Array("Mango", "PineApple", myArray1);
result = myArray2.toSource();
Array.toString()
Syntax
array.toString()
Description
The toString() method returns one string that contains all the elements in the array separated with commas. This method will automatically convert an array to a string when the array is used in string context.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
document.write(myArray1);
Array.unshift()
Syntax
array.unshift(arg1,...,argN)
Description
The unshift() method adds the arguments listed in the parameter list to the front of the array as new elements. Existing elements are shifted up to allow room for the new elements. The method returns the length of the array after adding the new elements.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
newLength = myArray1.unshift("blue", "black");
Array.valueOf()
Syntax
array.valueOf()
Description
The valueOf() method returns the primitive value of the object. In terms of an instance of an Array object, this method returns the array elements separated by commas. If an array contains another array, the contents are flattened when this method is used.
Example
myArray1 = new Array("red", "orange", "purple", "green", "yellow");
myArray2 = new Array("Mango", "PineApple", myArray1);
document.write(myArray2.valueOf());
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