Hypertext Preprocessor/ PHP(or simply PHP) is a general-purpose programming language originally designed for web development. It was originally created by Rasmus Lerdorf in 1994;[6] the PHP reference implementation is now produced by The PHP Group.[7] PHP originally stood for Personal Home Page,[6] but it now stands for the recursive initialism PHP: Hypertext Preprocessor.[8]
PHP code may be executed with a command-line interface (CLI), embedded into HTML code, or used in combination with various web template systems, web content management systems, and web frameworks. PHP code is usually processed by a PHP interpreter implemented as a module in a web server or as a Common Gateway Interface (CGI) executable.
PHP Example
In this tutorial, you will get a lot of PHP examples to understand the topic well. You must save the PHP file with a .php extension. Let’s see a simple PHP example.
File: hello.php
<!DOCTYPE>
<html>
<body>
<?php
echo “<h2>Hello by PHP</h2>“;
?>
</body>
</html>
PHP Variable Types
The main way to store information in the middle of a PHP program is by using a variable.
Here are the most important things to know about variables in PHP.
All variables in PHP are denoted with a leading dollar sign ($).
The value of a variable is the value of its most recent assignment.
Variables are assigned with the = operator, with the variable on the left-hand side and the expression to be evaluated on the right.
Variables can but do not need, to be declared before assignment.
Variables in PHP do not have intrinsic types – a variable does not know in advance whether it will be used to store a number or a string of characters.
Variables used before they are assigned have default values.
PHP does a good job of automatically converting types from one to another when necessary.
PHP variables are Perl-like.
PHP has a total of eight data types which we use to construct our variables −
Integers − are whole numbers, without a decimal point, like 4195.
Doubles − are floating-point numbers, like 3.14159 or 49.1.
Booleans − have only two possible values either true or false.
NULL − is a special type that only has one value: NULL.
Strings − are sequences of characters, like ‘PHP supports string operations.’
Arrays − are named and indexed collections of other values.
Objects − are instances of programmer-defined classes, which can package up both other kinds of values and functions that are specific to the class.
Resources − are special variables that hold references to resources external to PHP (such as database connections).
The PHP team is glad to announce the first beta release of PHP 7.4: PHP 7.4.0beta1. This continues the PHP 7.4 release cycle, the rough outline of which is specified in the PHP Wiki.
For source downloads of PHP 7.4.0beta1 please visit the download page.
Please carefully test this version and report any issues found in the bug reporting system.
Please DO NOT use this version in production, it is an early test version.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Beta 2, planned for August 8th.
The PHP team is glad to announce the release of the third PHP 7.4.0 version, PHP 7.4.0 Alpha 3. This continues the PHP 7.4 release cycle, the rough outline of which is specified in the PHP Wiki.
For source downloads of PHP 7.4.0 Alpha 3 please visit the download page.
Please carefully test this version and report any issues found in the bug reporting system.
Please DO NOT use this version in production, it is an early test version.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Beta 1, planned for July 25th.
The PHP team is glad to announce the release of the second PHP 7.4.0 version, PHP 7.4.0 Alpha 2. This continues the PHP 7.4 release cycle, the rough outline of which is specified in the PHP Wiki.
For source downloads of PHP 7.4.0 Alpha 2 please visit the download page.
Please carefully test this version and report any issues found in the bug reporting system.
Please DO NOT use this version in production, it is an early test version.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Alpha 3, planned for July 11th.
The PHP team is glad to announce the release of the first PHP 7.4.0 version, PHP 7.4.0 Alpha 1. This starts the PHP 7.4 release cycle, the rough outline of which is specified in the PHP Wiki.
For source downloads of PHP 7.4.0 Alpha 1 please visit the download page.
Please carefully test this version and report any issues found in the bug reporting system.
Please DO NOT use this version in production, it is an early test version.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Alpha 2, planned for June 27.
The PHP team is glad to announce the presumably last PHP 7.3.0 pre-release, PHP 7.3.0RC6. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC6 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be 7.3.0 (GA), planned for December 6th.
The PHP team is glad to announce the next PHP 7.3.0 pre-release, PHP 7.3.0RC5. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC5 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC6, planned for November 22nd.
The PHP team is glad to announce the next PHP 7.3.0 pre-release, PHP 7.3.0RC4. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC4 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC5, planned for November 8th.
The PHP team is glad to announce the next PHP 7.3.0 pre-release, PHP 7.3.0RC3. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC3 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC4, planned for October 25th.
The PHP team is glad to announce the next PHP 7.3.0 pre-release, PHP 7.3.0RC2. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC2 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC3, planned for October 11th.
The PHP team is glad to announce the release of the next PHP 7.3.0 pre-release, PHP 7.3.0RC1. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0RC1 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC2, planned for September 27th.
The PHP team is glad to announce the release of the seventh PHP 7.3.0 version, PHP 7.3.0beta3. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0beta3 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be RC1, planned for September 13th.
The PHP team is glad to announce the release of the sixth PHP 7.3.0 version, PHP 7.3.0beta2. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0beta2 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.
The next release would be Beta 3, planned for August 30th.
The PHP team is glad to announce the release of the fifth PHP 7.3.0 version, PHP 7.3.0beta1. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0beta1 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Beta 2, planned for August 16th.
The PHP team is glad to announce the release of the fourth PHP 7.3.0 version, PHP 7.3.0alpha4. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0alpha4 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Beta 1, planned for August 2nd.
The PHP team is glad to announce the release of the third PHP 7.3.0 version, PHP 7.3.0 Alpha 3. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0 Alpha 3 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Beta 1, planned for July 19th.
The PHP team is glad to announce the release of the second PHP 7.3.0 version, PHP 7.3.0 Alpha 2. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
For source downloads of PHP 7.3.0 Alpha 2 please visit the download page. Windows sources and binaries can be found on windows.php.net/qa/.
Please carefully test this version and report any issues found in the bug reporting system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Alpha 3, planned for July 5
The PHP team is glad to announce the release of the first PHP 7.3.0 version, PHP 7.3.0 Alpha 1. This starts the PHP 7.3 release cycle, the rough outline of which is specified in the PHP Wiki.
For source downloads of PHP 7.3.0 Alpha 1 please visit the download page.
Please carefully test this version and report any issues found in the bug reporting system.
Please DO NOT use this version in production, it is an early test version.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
The next release would be Alpha 2, planned for June 21.
The PHP development team announces the immediate availability of PHP 7.2.0 RC4. This release is the fourth Release Candidate for 7.2.0. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
For source downloads of PHP 7.2.0 Release Candidate 4 please visit the download page, Windows sources and binaries can be found atwindows.php.net/qa/.
The next Release Candidate will be announced on the 26th of October. You can also read the full list of planned releases on our wiki.
The PHP development team announces the immediate availability of PHP 7.2.0 RC3. This release is the third Release Candidate for 7.2.0. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
For source downloads of PHP 7.2.0 Release Candidate 3 please visit the download page, Windows sources and binaries can be found atwindows.php.net/qa/.
The next Release Candidate will be announced on the 12th of October. You can also read the full list of planned releases on our wiki.
The PHP development team announces the immediate availability of PHP 7.2.0 Release Candidate 1. This release is the first Release Candidate for 7.2.0. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
For source downloads of PHP 7.2.0 Release Candidate 1 please visit the download page, Windows sources and binaries can be found atwindows.php.net/qa/.
The second Release Candidate will be released on the 14th of September. You can also read the full list of planned releases on our wiki.
The PHP development team announces the immediate availability of PHP 7.2.0 Beta 3. This release is the third and final beta for 7.2.0. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
For source downloads of PHP 7.2.0 Beta 3 please visit the download page, Windows sources and binaries can be found atwindows.php.net/qa/.
The first Release Candidate will be released on the 31th of August. You can also read the full list of planned releases on our wiki.
The PHP development team announces the immediate availability of PHP 7.2.0 Alpha 3. This release contains fixes and improvements relative to Alpha 2. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
THIS IS A DEVELOPMENT PREVIEW – DO NOT USE IT IN PRODUCTION!
For information on new features and other changes, you can read the NEWS file or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive.
For source downloads of PHP 7.2.0 Alpha 3 please visit the download page, Windows sources and binaries can be found on windows.php.net/qa/.
1 <?php 2 abstractclassUser{ 3 publicstring$name; 4 5 publicfunction__construct(string$name){ 6 $this->name=$name; 7 } 8 9 publicfunctiongreet():string{10 return"Hello, my name is ".$this->name;11 }12 13 abstractpublicfunctionjob():string;14 }15 16 classStudentextendsUser{17 publicstring$course;18 19 publicfunction__construct(string$name,string$course){20 $this->course=$course;21 parent::__construct($name);22 }23 24 publicfunctionjob():string{25 return"I learn ".$this->course;26 }27 }28 29 classTeacherextendsUser{30 publicarray$teachingCourses;31 32 publicfunction__construct(string$name,string...$teachingCourses){33 $this->teachingCourses=$teachingCourses;34 parent::__construct($name);35 }36 37 publicfunctionjob():string{38 return"I teach ".implode(", ",$this->teachingCourses);39 }40 }41 42 $students=[43 newStudent("Alice","Computer Science"),44 newStudent("Bob","Computer Science"),45 newStudent("Charlie","Business Studies"),46 ];47 $teachers=[48 newTeacher("Dan","Computer Science","Information Security"),49 newTeacher("Erin","Computer Science","3D Graphics Programming"),50 newTeacher("Frankie","Online Marketing","Business Studies","E-commerce"),51 ];52 53 echo"Students: n";54 foreach($studentsas$student){55 echo$student->greet().", ".$student->job()."n";56 }57 58 echo"Teachers: n";59 foreach($teachersas$teacher){60 echo$teacher->greet().", ".$teacher->job()."n";61 }62 63 // Output of program:64 // Students:65 // Hello, my name is Alice, I learn Computer Science66 // Hello, my name is Bob, I learn Computer Science67 // Hello, my name is Charlie, I learn Business Studies68 // Teachers:69 // Hello, my name is Dan, I teach Computer Science, Information Security70 // Hello, my name is Erin, I teach Computer Science, 3D Graphics Programming71 // Hello, my name is Frankie, I teach Online Marketing, Business Studies, E-commerce
Functions of PHP
PHP defines a large array of functions in the core language and many are also available in various extensions; these functions are well documented in the online PHP documentation.[rx]However, the built-in library has a wide variety of naming conventions and associated inconsistencies, as described under history above.
PHP is a general-purpose scripting language that is especially suited to server-side web development, in which case PHP generally runs on a web server. Any PHP code in a requested file is executed by the PHP runtime, usually to create dynamic web page content or dynamic images used on websites or elsewhere.[rx] It can also be used for command-line scripting and client-side graphical user interface (GUI) applications. PHP can be deployed on most web servers, many operating systems and platforms, and can be used with many relational database management systems (RDBMS). Most web hosting providers support PHP for use by their clients. It is available free of charge, and the PHP Group provides the complete source code for users to build, customize and extend for their own use.[rx]
Dynamic web page: example of server-side scripting (PHP and MySQL).
PHP acts primarily as a filter,taking input from a file or stream containing text and/or PHP instructions and outputting another stream of data. Most commonly the output will be HTML, although it could be JSON, XML or binary data such as image or audio formats. Since PHP 4, the PHP parser compiles input to produce bytecode for processing by the Zend Engine, giving improved performance over its interpreter predecessor.[rx]
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