Introduction to [] and {} object usage in JavaScript _javascript tips

Copy Code code as follows:

var a=["Apple", "Peach", "Banala"];

This is another way of defining an array, which is equivalent to

Copy Code code as follows:

var a=new Array ();
A.push ("Apple");
A.push ("Peach");
A.push ("Banala");

Copy Code code as follows:

var b={a: "Apple", p: "Peach", B: "Banala"};

This is a JSON object
There are two simple special symbols [] and {}. They are the form of an object where [] not only can you represent an array, you can set values and access values directly from the object's properties. For example:

Copy Code code as follows:

var c=[];
C["A"]= "Apple";
c["B"]= "Banala";

Or

Copy Code code as follows:

var c={};
C["A"]= "Apple";
c["B"]= "Banala";

Their function and function are the same, only a small difference, said later.
Access can be accessed directly by the attribute:

Copy Code code as follows:

Alert (c["a"]);

Displays "Apple".
To traverse, you can pass:

Copy Code code as follows:

<pre class=html name= "code" >for (Var key in C)
Alert (C[key]);</pre>
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This will show all the property values.
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<P> of course, there is a each traversal in jquery, and you can access individual properties and values. But this is only when </P>
<pre class=javascript name= "code" >var c={};</pre> situation, if it is
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<pre class=html name= "code" ><pre class=html name= "code" >var
You can't. <BR>
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<P> then use </P>
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<pre class=javascript name= "code" >$.each (c, Function (key, Val) {
Alert (key+ ":" +val);
});</pre><br>
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<P> using objects is convenient, more efficient than using arrays, the time complexity of finding a value in an array is O (n), and the time complexity of using an object is only O (1), so in most cases the object is used to store the value. </P>
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