PHP Tutorials - Herong's Tutorial Examples - v5.17, by Herong Yang
What Is an Object
This section describes what is an object - a data entity that is created as an instance of a class. Objects are created with the 'new' operator.
What Is an Object? An object is a data entity that is created as an instance of a class.
In PHP, an object is created with the "new" operator, which returns an identifier to the object. For example, the following statement create an object of the "HelloClass" class and assigned the identifier of the object to variable $h:
$h = new HelloClass();
In order to retrieve a property value or invoke an operation of object, we need to use the "->" operator attached to the object identifier. For example, the following statement invokes the "show()" operation on the object identified by "$h":
$h->show();
Here is a complete PHP script that defines a class, creates an object and invoke an operation on the object:
<?php /* HelloClassDemo.php #- Copyright 2015 (c) HerongYang.com. All Rights Reserved. */ class HelloClass { public function show() { echo "Hello world!\n"; } } $h = new HelloClass(); $h->show(); ?>
If you run the above tutorial example, you will get:
herong> \php\php HelloClassDemo.php Hello world!
Table of Contents
Introduction and Installation of PHP
PHP Data Types and Data Literals
Variables, References, and Constants
Expressions, Operations and Type Conversions
Conditional Statements - "if" and "switch"
Loop Statements - "while", "for", and "do ... while"
Function Declaration, Arguments, and Return Values
Interface with Operating System
►Introduction of Class and Object
What Is a Superclass and a Subclass
What Is an Overloaded Property
What Is Object Property Iteration
Updating Variables Who Share an Object
Passing Objects as Function Arguments
Integrating PHP with Apache Web Server
Retrieving Information from HTTP Requests
Creating and Managing Sessions in PHP Scripts
Sending and Receiving Cookies in PHP Scripts
Controlling HTTP Response Header Lines in PHP Scripts
MySQL Server Connection and Access Functions
Functions to Manage Directories, Files and Images
SOAP Extension Function and Calling Web Services
SOAP Server Functions and Examples
Localization Overview of Web Applications
Using Non-ASCII Characters in HTML Documents
Using Non-ASCII Characters as PHP Script String Literals
Receiving Non-ASCII Characters from Input Forms
"mbstring" Extension and Non-ASCII Encoding Management
Managing Non-ASCII Character Strings with MySQL Servers
Parsing and Managing HTML Documents
Configuring and Sending Out Emails
Managing PHP Engine and Modules on macOS