Javascript array and dictionary usage analysis_javascript skills

This article analyzes the usage of Javascript arrays and dictionaries with examples. Share it with everyone for your reference. The specific analysis is as follows:

Javascript’s array Array is both an array and a dictionary.

Let’s take an example to see how to use arrays.

Copy code The code is as follows:

var a = new Array();
a[0] = "Acer";
a[1] = "Dell";
for (var i in a) {
alert(i);                                 }

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

Then traverse the array. Note that the result of i is 0 and 1, and the result of a[i] is a string.

This is very similar to traversing the properties of objects mentioned in the previous article.

Let’s take a look at how to use the dictionary.

Copy code The code is as follows:

var computer_price = new Array();

computer_price["Acer"] = 500;
computer_price["Dell"] = 600;
alert(computer_price["Acer"]);

We can even iterate over this array (dictionary) as above

Copy code The code is as follows:

for (var i in computer_price) {

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

Here i is each key value of the dictionary. The output result is:
Acer: 500

Dell: 600

Next, let’s take a look at the interesting part of Javascript, still the above example.

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

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

Let’s take a look at the simplified declaration methods of dictionaries and arrays.

Copy code The code is as follows:

var array = [1, 2, 3]; // Array

var array2 = { "Acer": 500, "Dell": 600 }; // Dictionary
alert(array2.Acer); // 50

This declaration of the dictionary is the same as the previous one. In our example, Acer is a key value and can also be used as an attribute of the dictionary object.

I hope this article will be helpful to everyone’s JavaScript programming design.