Introduction to php php++
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PHP originated as a tool for personal home pages created by Rasmus Lerdorf. It is now known as the PHP Hypertext Processor and is an open source, scripting language commonly used for web development. PHP scripts can be embedded into HTML pages and allow for easy access to form data and output of dynamic HTML. PHP is a procedural language like C with some object-oriented features. It has an extensive function library that supports tasks like string handling, dates/times, files, databases and more. PHP follows a model where scripts run on the server and generate HTML to be sent to the client browser.
![C-like language
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Free format - white space is ignored
Statements are terminated by semi-colon ;
Statements grouped by { … }
Comments begin with // or a set of comments /* */
Assignment is ‘=’: $a=6
Relational operators are ,< , > == ( not a single equal)
Control structures include if (cond) {..} else { }, while (cond) { .. } ,
for(sstartcond; increment; endcond) { }
Arrays are accessed with [ ] : $x[4] is the 5th element of the array
$x – indexes start at 0
Associative Arrays (hash array in Perl, dictionary in Java) are
accessed in the same way: $y[“fred”]
Functions are called with the name followed by arguments in a fixed
order enclosed in ( ) : substr(“fred”,0,2)
Case sensitive - $fred is a different variable to $FRED](https://image.slidesharecdn.com/introductiontophp-140305023336-phpapp02/85/Introduction-to-php-php-6-320.jpg)
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Introduction to php php++
- 2. PHP Origins Rasmus Lerdorf (born Greenland, ed Canada) PHP originally abbreviation for ‘Personal Home Pages’, now ‘PHP Hypertext Processor’ Other key developers: Zeev Surashi and Andi Gutmans (Israel) Open Source PHP version 4.4.3 current at UWE Due to upgrade to PHP 5
- 3. Scripting languages • A scripting language is: – – – – – – – – – often evolved not designed cross-platform since interpreter is easy to port designed to support a specific task – PHP -> Web support un-typed variables (but values are typed) implicit variable declaration implicit type conversion stored only as script files compiled on demand may run on the server (PHP) or the client (Javascript) • What design and development are involved in using a scripting language like PHP for development in place of a compiled language (Java in JSP, .NET)?
- 4. PHP details • Procedural language – Compare with Javascript which is event-driven • C-like syntax - { } ; • Extensive Function Library • Good Web-server integration – Script embedded in HTML – Easy access to form data and output of HTML pages • Not fully object-oriented – Java is fully object oriented – all functions have to be in a class – In PHP, classes are additional but quite simple to use
- 5. PHP and HTML • HTML-embedded – PHP scripts are essentially HTML pages with the occasional section of PHP script. – PHP script is enclosed in the tag pair: • <?php print date(“H:I”) ?>
- 6. C-like language • • • • • • • • • • • Free format - white space is ignored Statements are terminated by semi-colon ; Statements grouped by { … } Comments begin with // or a set of comments /* */ Assignment is ‘=’: $a=6 Relational operators are ,< , > == ( not a single equal) Control structures include if (cond) {..} else { }, while (cond) { .. } , for(sstartcond; increment; endcond) { } Arrays are accessed with [ ] : $x[4] is the 5th element of the array $x – indexes start at 0 Associative Arrays (hash array in Perl, dictionary in Java) are accessed in the same way: $y[“fred”] Functions are called with the name followed by arguments in a fixed order enclosed in ( ) : substr(“fred”,0,2) Case sensitive - $fred is a different variable to $FRED
- 7. Function library • Basic tasks – – – – – String Handling Mathematics – random numbers, trig functions.. Regular Expressions Date and time handling File Input and Output • And more specific functions for– Database interaction – • MySQL, Oracle, Postgres, Sybase, MSSQL .. – – – – – Encryption Text translation Spell-checking Image creation XML
- 8. String Handling • String literals (constants) enclosed in double quotes “ ” or single quotes ‘ ’ • Within “”, variables are replaced by their value: – called variable interpolation. “My name is $name, I think” • Within single quoted strings, interpolation doesn’t occur • Strings are concatenated (joined end to end) with the dot operator “key”.”board” == “keyboard” • Standard functions exist: strlen(), substr() etc • Values of other types can be easily converted to and from strings – numbers implicitly converted to strings in a string context. • Regular expressions be used for complex pattern matching.
- 9. 3(+1) Tier architecture voice DHTML touch Browser (IE, FireFox, Opera) vision HTTP SQL PHP script HTML Web Server (Apache, IIS) Database tables Desktop (PC or MAC) Database Server SMS Web Service SMS system Client application Remote services
- 10. Learning PHP • Start with just the basics, installing a script to output an HTML page • Understand how PHP supports interaction with the Browser or other clients • Understand how PHP supports integration with databases – MySQL • Understand how PHP supports integration with other applications – Web services