PhPbasics

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Introduction to php basics

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PHP: The Basics:

PHP: The Basics By : Mr. Shehrevar Davierwala Only for educational Purpose

What is it?:

What is it? PHP is a scripting language commonly used on web servers. Stands for “PHP: Hypertext Preprocessor” Open source Embedded code Comparable with ASP Multiple operating systems/web servers Only for educational Purpose

The PHP Resource:

The PHP Resource www.php.net Only for educational Purpose

What can it do?:

What can it do? Dynamic generation of web-page content Database interaction Processing of user supplied data Email File handling Text processing Network interaction And more… Only for educational Purpose

Fundamentals:

Fundamentals PHP is embedded within xhtml pages within the tags: <?php … ?> The short version of these tags can also be used: <? … ?> Each line of PHP is terminated, like MySQL, with a semi-colon. Only for educational Purpose

Hello World!:

Hello World! <html> <head> <title>PHP Test</title> </head> <body> <?php echo ‘<p>Hello World!</p>’ ; ?> </body> </html> Only for educational Purpose

Preparing to code with PHP:

Preparing to code with PHP Only for educational Purpose

Literals..:

Literals.. All strings must be enclosed in single of double quotes: ‘Hello’ or “Hello” . Numbers are not in enclosed in quotes: 1 or 45 or 34.564 Booleans (true/flase) can be written directly as true or false . Only for educational Purpose

Comments:

Comments // This is a comment # This is also a comment /* This is a comment that is spread over multiple lines */ Do not nest multi-line comments // recommended over # Only for educational Purpose

Comments:

Comments <?php // this is a comment echo ‘Hello World!’ ; /* another multi-line comment */ ?> Only for educational Purpose

Displaying Data:

Displaying Data There are two language constructs available to display data: print () and echo (). They can be used with or without brackets. Note that the data ‘displayed’ by PHP is actually parsed by your browser as HTML. View source to see actual output. Only for educational Purpose

Displaying data:

Displaying data <?php echo ‘Hello World!<br />’ ; echo ( ‘Hello World!<br />’ ); print ‘Hello World!<br />’ ; print ( ‘Hello World!<br />’ ); ?> Only for educational Purpose

Escaping Characters:

Escaping Characters Some characters are considered ‘special’ Escape these with a backslash \ Special characters will be flagged when they arise, for example a double or single quote belong in this group… Only for educational Purpose

Escaping Characters:

Escaping Characters <?php // Claire O’Reilly said “Hello”. echo ‘Claire O\’Reilly ’ ; echo “said \”Hello\”.” ; ?> Only for educational Purpose

Variables: What are they?:

Variables: What are they? When we work in PHP, we often need a labelled place to store a value (be it a string, number, whatever) so we can use it in multiple places in our script. These labelled ‘places’ are called VARIABLES Only for educational Purpose

Variables: Naming:

Variables: Naming $ followed by variable name Case sensitive $variable differs from $Variable Stick to lower-case to be sure! Name must started with a letter or an underscore Followed by any number of letters, numbers and underscores Only for educational Purpose

Variables: example:

Variables: example <?php $name = ‘Phil’ ; $age = 23; echo $name; echo ’ is ‘ ; echo $age; // Phil is 23 ?> Only for educational Purpose

Constants:

Constants Constants (unchangeable variables) can also be defined. Each constant is given a name (note no preceding dollar is applied here). By convention, constant names are usually in UPPERCASE. Only for educational Purpose

Constants:

Constants <?php define ( ‘NAME’ , ‘Phil’ ); define ( ‘AGE’ ,23); echo NAME; echo ’ is ‘ ; echo AGE; // Phil is 23 ?> Only for educational Purpose

“ or ‘ ?:

“ or ‘ ? There is a difference between strings written in single and double quotes. In a double-quoted string any variable names are expanded to their values. In a single-quoted string, no variable expansion takes place. Only for educational Purpose

“ or ‘ ?:

“ or ‘ ? <?php $name = ‘Phil’ ; $age = 23; echo “$name is $age” ; // Phil is 23 ?> Only for educational Purpose

“ or ‘ ?:

“ or ‘ ? <?php $name = ‘Phil’ ; $age = 23; echo ‘$name is $age’ ; // $name is $age ?> Only for educational Purpose

Review:

Review We’ve started PHP.. Escaping XHTML Comments Basic Syntax Variables Constants Only for educational Purpose

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