PHP | Namespace - GeeksforGeeks

Like C++, PHP Namespaces are the way of encapsulating items so that same names can be reused without name conflicts.

It can be seen as an abstract concept in many places. It allows redeclaring the same functions/classes/interfaces/constant functions in the separate namespace without getting the fatal error.
A namespace is a hierarchically labeled code block holding a regular PHP code.
A namespace can contain valid PHP code.
Namespace affects following types of code: classes (including abstracts and traits), interfaces, functions, and constants.
Namespaces are declared using the namespace keyword.

A namespace must be declared the namespace at the top of the file before any other code – with one exception: the declare keyword.

<?php  
namespace MyNamspaceName { 
   
    // Regular PHP code  
    function hello()  
    { 
        echo 'Hello I am Running from a namespace!'; 
    } 
} 
?> 

If namespace is declared globally, then declare it without any name.

<?php  
namespace { 
   
    // Global space! 
} 
?> 

Multiple namespaces can be declared within a single PHP code.

<?php 
namespace MyNamespace1 { 
   
} 
    
namespace MyNamespace2 { 
   
} 
    
namespace { 
   
} 
?> 

A namespace is used to avoid conflicting definitions and introduce more flexibility and organization in the code base. Just like directories, namespace can contain a hierarchy know as subnamespaces. PHP uses the backslash as its namespace separator.

Example:

<?php 
namespace MyNamespaceName; 
function hello()  
    { 
        echo 'Hello I am Running from a namespace!'; 
    } 
    
// Resolves to MyNamespaceName\hello 
hello(); 
  
// Explicitly resolves to MyNamespaceName\hello 
namespace\hello(); 
?> 

Aliasing in Namespaces

Importing is achieved by using the ‘use’ keyword. Optionally, It can specify a custom alias with the ‘as’ keyword.
Example:

<?php 
namespace MyNamespaceName; 
    
require 'project/database/connection.php'; 
    
use Project\Database\Connection as Connection; 
    
$connection = new Connection(); 
    
use Project\Database as Database; 
    
$connection = new Database\Connection(); 
?> 

It is possible to dynamically call namespaced code, dynamic importing is not supported.

<?php 
namespace OtherProject; 
    
$title = 'geeks'; 
    
// This is valid PHP 
require 'project/blog/title/' . $title . '.php'; 
    
// This is not 
use Project\Blog\title\$title; 
?> 

Reference : http://php.net/manual/en/language.namespaces.php

My Personal Notes

Jun	JUL	Aug
	20
2018	2019	2020

Suggest a Topic

Recommended Posts: