Php
/
OOP
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Quotes S
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Constants S
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Control structures S
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Reference S
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Number systems S
- 2 Variables 4
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Definition S
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Variable variable S
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Exists S
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Type casting S
- 3 Operators 5
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Aritmetic S
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Bitwise S
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String S
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Comparison S
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Logical S
- 4 Function 4
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Definition S
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Anonymous S
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Reference S
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Variable arguments S
- 5 Array 7
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Basics S
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Operations S
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Create S
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Search S
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Modify S
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Sort S
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Storage S
- 6 String 9
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Basics
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Compare
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Search
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Replace
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Format
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Regexp
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Parse
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Formating
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Json
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File open
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Read file
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Read csv
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File contents
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Context
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Ob_start
- 8 Oop 6
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Object instantiation S
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Class constructor
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Interfaces, abstract
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Resource visibility
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Class constants
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Namespaces
- 9 Features 9
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Autoload
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Class reflection
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Magic methods
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Exceptions S
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Late static binding
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Type hinting
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SPL
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PHPUNIT
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PHAR
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Php7.4 S
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Php8.0 S
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Headers
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File Uploads
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Cookies
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Observer Pattern
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Strategy Pattern
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Registry
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Slim Framework
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App
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Symfony v5
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Guzzle
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Routes S
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Flex
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Doctrine
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Templating
R
Q
Abstract
Abstract and Interfaces are design to create a series of constrains. Here the class fails to proper implement interface methods.
code
abstract class myAdapter
{
private $id;
abstract function insert();
abstract function update();
public function save()
{
// ...
}
}
class PDO_myAdapter extends myAdapter{
public function __construct($dsn)
{
// ...
}
public function insertAdapter()
{
// wrong method name
// it should be insert()
}
public function update()
{
// ...
}
// Fatal error: Class PDO_myAdapter contains 1 abstract method ...
// myAdapter::insert()
}
Interface
Interfaces specifies an API that a class must implement. Interfaces contain no body. Here the class method save() is not compatible with the interface.
code
interface myAdapter
{
public function insert();
public function update();
public function save($name=null);
}
class PDO_Adapter implements myAdapter
{
public function insert()
{
// ...
}
public function update()
{
// ...
}
public function save($name)
{
// wrong
}
// Fatal error
// must be compatible with myAdapter::save($name = NULL)
}
Extend
A class can only extend only one parent. It can implement multiple interfaces.
class PDO_Adapter extends PDO
implements myAdapter, SeekableIterator
{
// ...
}
Check instance
You can check if an object is an instance of a particular class.
code
class A
{
// ...
}
$obj = new A();
if ($obj instanceof A) { // true
echo "Object is an instance of A";
}
➥ Questions
Last update: 516 days ago