Question: What is namespace in PHP?
namespace is reserve keywords which is used to encapsulating the class, method, data member variables and static methods.
Question: Benefits of namespace in PHP?
- Encapsulate the data which fixed collisions between code you create, and internal PHP classes/functions/constants.
- Ability to alias which improved the readability of source code.
Question: Which PHP Version support namespaces?
PHP5.3
Question: How namespaces are defined?
namespaces are defined with keyword namespace
For Example:
namespace math
Question: Example - Simple class without namespace (OR Global namespace)?
File: /myproject/simple-file.php
class mathSimple {
function add($a, $b) {
return $a + $b;
}
}
File: /myproject/run-example.php
include "simple-file.php"; $obj1 = new mathSimple(); //calling for Global Namespace echo $obj1->add(10,20);//30
When we execute run-example.php file, it will return 30
Question: Example - Simple class with namespace?
File: /myproject/namespace-file.php
namespace math;
class mathSimple {
function add() {
return array_sum(func_get_args()) ;
}
}
File: /myproject/run-example.php
namespace math; include "simple-file.php"; include "namespace-file.php"; $obj1 = new \mathSimple(); //calling for Global Namespace echo $obj1->add(10,20,30); echo "\n"; $obj2 = new mathSimple(); //calling for namespace math echo $obj2->add(10,20,30);Question: How to import namespaces?
use Zend\View\Model\ViewModel;
Question: How to use alias namespaces for import namespace?
use Zend\View\Model\ViewModel as ZendViewModel;
Question: Can we override the php in-built using namespace?
Yes, We can do. File: /myproject/namespace-file2.php
namespace math;
class mathSimple {
function add() {
return array_sum(func_get_args()) ;
}
}
function strlen($string){
return 'in built functi';
}
File: /myproject/run-example2.php
namespace math;
include "namespace-file2.php";
echo strlen('string'); //calling namespace function
echo \strlen('strlen'); //calling inbuilt function