JavaScript Array and How It’s Different from Object
It’s important to know arrays and objects in JavaScript because they are often used to store client-side data. Below are quick points on arrays and objects:
// arrays and objects can be confusing at first
// just remember that arrays in Javascript are ordered lists
// and are normally looped through using numerical index starting with 0
// objects, on the other hand, have property names associated with values
// confusion always happen when objects are used like associative arrays,
// arrays that use names as index to access their associated values
// declaring an array
// as an empty array
var myArray1 = [];
alert(myArray1.length); // displays 0, since it”s empty
// with initialized values
var myArray2 = [“apple”, “orange”, “banana”, “strawberry”];
alert(myArray2[1]); // displays orange, the second element in the array
// using Array constructor
var myArray3 = new Array(“red”, “green”, “blue”);
alert(myArray3.join(“, “)); // displays red, green, blue
// object on the other hand has a different declaration syntax
// while array is declared using square brackets [],
// object is declared using curly braces {}
// BUT both use [] to access their elements/properties
var myObject1 = {};
var myObject2 = {
“fruit1”: “apple”,
“fruit2”: “orange”,
“fruit3”: “banana”,
“fruit4”: “strawberry”
}
alert(myObject2[“fruit2”]); // displays orange
// one method that is quite used most often for arrays is the push() method
// it”s a convenient way to add to your array
alert(myArray2.length); // displays 4
myArray2.push(“grape”);
myArray2.push(“cherry”);
alert(myArray2.length); // displays 6, after adding 2 more in the array
Hopefully that helps clarify the confusion.
JavaScript Kit has a comprehensive reference with explanations and examples including reference to Array object that you might want to look further into; definitely a good resource to add to your toolbox. I already had it added to my Favorite Links.
Also, Fun with JavaScript Native Array Functions talks about a slew of array functions in detail.