How to define the namespace of a PHP namespace

This article mainly introduces how to define the namespace of the PHP namespace, and analyzes in detail the definition methods and precautions of the namespace and sub-namespace of the php namespace in combination with the instance form, for more information about how to define the namespace of a PHP namespace, the definitions and precautions of php namespaces and sub-namespaces are analyzed in detail based on the instance form. For more information, see

This document describes how to define the namespace of a PHP namespace. We will share this with you for your reference. The details are as follows:

Define a namespace

I don't want to explain the name of a space here. a better explanation is to prove it using an example:

For example:

The following code is a file in "test. php:

Namespace Test; class Test {public function Ttest () {echo "this is the Test method in Test "."
";}}

Next, I will use three different access methods. I will write these three access programs in a file named "index. php:

Method 1:

namespace Index;require 'test.php';$T=new \Test\Test();$T->Ttest();

The result is:

This is the Test method in Test.

Method 2:

namespace Index;namespace Test;require 'test.php';$T=new Test();$T->Ttest();

The result is:

This is the Test method in Test.

Method 3:

namespace Index;require 'test.php';use Test\Test;$T=new Test();$T->Ttest();

The result is:

This is the Test method in Test.

Note: namespace Index can be written or not written. this is only the name of the index. php file space. The results of these three methods are the same.

Define a sub-namespace

Definition:

It has a similar relationship with directories and files. The PHP namespace also allows you to specify a hierarchical namespace name. Therefore, namespace names can be defined in different layers.

For example, this is my custom project directory:

One. php

namespace projectOne\one;class Test{    public function test(){     return "this is a test program";    }}

To access the Test () method under the test class in one. php, the code in Two is as follows:

Two. php

namespace projectOne\one;require '../projectOne/One.php';$O=new Test();echo $O->test();

Output: this is a test program

Define multiple namespaces in the same file and access each other

Test. php

namespace projectOne\one{    class test{      public function hello(){        return "helloworld";      }    }}namespace projectOne\Two{    class project{      public function world2(){        return "welcome to china";      }    }    class project2 extends \projectOne\one\test{      public function wo(){        return "this is my test function ,it is name wo";      }    }}namespace projectOne\Two{    $p=new project2();    echo $p->wo()."
";    echo $p->hello();}

Output: this is my test function, it is name wo
Helloworld

The above is a detailed description of the namespace definition method of the PHP namespace. For more information, see other related articles in the first PHP community!