Javascript array and dictionary usage analysis

This article analyzes the Javascript array and dictionary usage as an example. Share with you for your reference. The specific analysis is as follows:

Javascript array Array, is both an array and a dictionary (Dictionary).

Let's start with an example of array usage.

var a = new Array();  

a[0] = "Acer";  

a[1] = "Dell";  

for (var i in a) {  

    alert(i);          

}

The above code creates an array where each element is a string object.

The array is then traversed. Note that i results in 0 and 1, a[i] results in string.

This is very much like the previous article about traversing the properties of an object.

Now let's look at the dictionary usage.

var computer_price = new Array();  

computer_price["Acer"] = 500;  

computer_price["Dell"] = 600;  

alert(computer_price["Acer"]);

We can even traverse the array (dictionary)
as above

for (var i in computer_price) {  

    alert(i + ": " + computer_price[i]);  

}

i here is each key value of the dictionary. The output is:

Acer: 500

Dell: 600

Now, let's see what's interesting about Javascript, again, the example above.

We can think of computer_price as a dictionary object, and each of its key values is an attribute.

That is, Acer is an attribute of computer_price. We can use it like this: computer_price.Acer

Let's take a look at simplified declarations for dictionaries and arrays.

var array = [1, 2, 3]; //  An array of   

var array2 = { "Acer": 500, "Dell": 600 }; //  The dictionary   

alert(array2.Acer); // 50

So the dictionary declaration is the same as before. In our example, Acer is again a key and an attribute of the dictionary object.

I hope that this article has been helpful to your javascript programming.