PHP Tutorial

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PHP Tutorial

• I-Ming Lee

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PHP Hypertext Preprocessor

• PHP is a server-side interpreted programming
  language used by web developers to create dynamic
  website which can interact and change based on
  users actions. PHP is used in over 3.5 million
  websites. It exists as one of the most widely
  used dynamic web scripting languages.

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PHP Functions

• PHP runs on different platforms (Windows, Linux,
  Unix, MacOS).
• PHP is a Server-Side Scripting language.
• PHP scripts are executed on the server.
• PHP code is embedded in HTML code.
• PHP has syntax very similar to other high-level
  languages (C, Python, Perl, ASP).
• PHP is an Open-Source software and is free to
  download and use.
• PHP is designed to perform very well with other
  open source web solutions (MySQL, Apache).

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PHP Installation

• Download PHP http//www.php.net/downloads.php
• Download MySQL Database http//www.mysql.com/down
  loads/index.html
• Download Apache Server http//httpd.apache.org/do
  wnload.cqi

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PHP Syntax

• CODE
• lt?php
• echo hello world!
• //prints the string hello world!
• ?gt
• All PHP code starts and ends with lt?php or lt? and
  ?gt tags
• Comments all begin with //
• echo is for output and the string is contained in
  double quotes.

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PHP Variables

• Variables are used for storing a values, like
  text strings, numbers or arrays.
• When a variable is declared, it can be used over
  and over again in users script.
• All variable in PHP start with a sign symbol.

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PHP Variable Example

• Creating a variable containing a string, and a
  variable containing a number
• lt?php
• txt Hello World!
• x 16
• ?gt

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Naming Rules for Variables

• A variable name must start with a letter or an
  underscore _
• A variable name can only contain alpha- numeric
  characters and underscore (a-z, A-Z, 0-9, _).
• A variable name should not contain spaces. If a
  variable name is more than one word, it should be
  separated with an _ (my_txt), or with
  capitalization (myTxt).

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PHP String Variables

• The PHP script assigns the text Hello World to
  a string variable called txt
• lt?php
• txt Hello World
• Echo txt
• ?gt
• The output Hello World

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PHP String Variables (Cont.)

• The concatenation operator (.) is used to put two
  string values together.
• lt?php
• txt1 Hello World!
• txt2 Whats up!
• echo txt1 . . txt2
• ?gt
• The output Hello World! Whats up!

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PHP String Variables (Cont.)

• The strlen() function is used to return the
  length of a string.
• lt?php
• echo strlen(Hello World!)
• ?gt
• The output 12.

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PHP String Variables (Cont.)

• The strpos() function is used to search for
  character within a string. If a match is found,
  it will return the position of the first match.
  If not found, it will return FALSE.
• lt?php
• echo strpos(Hello World!, World)
• ?gt
• The output 6
• Note that the first position in the string is 0.

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PHP Operators

• Arithmetic Operators

• Assignment Operators

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PHP Operators (Cont.)

• Assignment operators

• Comparison operators

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PHP IfElse Statements

• The if statement
• lt?php
• d date(D)
• if (d Fri) echo Have a nice weekend
• ?gt
• The ifelse statement
• lt?php
• d date(D)
• if (d Fri) echo Have a nice weekend
• else echo Have a nice day!
• ?gt

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PHP IfElse Statement (Cont.)

• The ifelseifelse statement
• lt?php
• d date(D)
• if (d Fri)
• echo Have a nice weekend
• elseif (d Sun)
• echo Have a nice Sunday!
• else echo Have a nice day!
• ?gt

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PHP Switch Statement

• Use the switch statement to select one of many
  blocks of code to be executed.
• lt?php
• Switch (x)
• case 1 echo Number 1 break
• case 2 echo Number 2 break
• case 3 echo Number 3 break
• default echo No number match
• ?gt

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PHP Arrays

• Numeric Arrays
• //the index are automatically assigned
• cars array(Honda, Volvo,, BMW,
  Toyota)
• //assign the index manually
• cars0 Honda
• cars1 Volvo
• cars2 BMW
• cars3 Toyota

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PHP Arrays (Cont.)

• Associative Arrays each ID key is associated
  with a value.
• ages array(Petergt32, Johngt30,
  Raygt28)
• OR
• agesPeter 32
• agesJohn 30
• agesRay 28

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PHP Arrays (Cont.)

• Multidimensional arrays
• families array
• (
• Griffin gt array
• ( Peter, Lois, Megan),
• Quagmire gt array
• (Glenn),
• Brown gt array
• (Cleveland,Junior)
• )
• echo Is.familiesGriffin1.in Griffin
  family?
• Output Is Lois in Griffin family?

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PHP While Loop

• While Loop
• lt?php
• i 0
• num 10
• While (ilt num)
• echo i
• i
• ?gt

• DoWhile Loop
• lt?php
• i 0
• num 10
• do
• echo i
• i
• while (iltnum)
• ?gt

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PHP For Loops

• The for Loop
• lt?php
• For(i0 ilt5 i)
• echo i
• ?gt

• The foreach loop is used to loop thru arrays.
• lt?php
• xarray(one,two, three)
• Foreach(x as value)
• echo value.
• ?gt

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PHP Functions

• Create PHP function
• Give the function a name that reflects what the
  function does.
• The function name can start with a letter or
  underscore. No number.

lt?php Function printName() Echo Jacky
Yo Echo My name is printName() ?gt
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PHP Functions (Cont.)

• Adding parameter
• lt?php
• function printName(fname)
• echo fname.Yo.ltbr/gt
• Echo My name is
• printNmae(Jacky)
• ?gt

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PHP Functions (Cont.)

• To let a function return a value, use the return
  statement.
• lt?php
• function add (x, y)
• total x y
• return total
• echo 1 10 .add(1,10)
• ?gt

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PHP Forms and User Input

• The PHP _GET and _POST variables are used to
  retrieve information from forms, like user input.
• The most important thing to notice when dealing
  with HTML forms and PHP is that any form element
  in an HTML page will automatically be available
  to your PHP scripts.

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PHP Forms and User Input (Cont.)

• The example contains an HTML form with two input
  fields and a submit button
• lthtmlgt
• ltbodygt
• ltform actionwelcome.php methodpostgt
• Nameltinput typetext namefname/gt
• Ageltinput typetext nameage/gt
• ltinput typesubmit/gt
• lt/formgt
• lt/bodygt
• lt/htmlgt

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PHP Forms and User Input (Cont.)

• After fill out the form and click on submit
  button, the form data is sent to a PHP file,
  called welcome.php
• //welcome.php
• lthtmlgt
• ltbodygt
• Welcome lt?php echo _POSTfname ?gt! ltbr/gt
• You are lt?php echo _POSTage ?gt years old.
• lt/bodygt
• lt/htmlgt

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PHP _GET Function

• The build-in _GET function is used to collect
  values in a form with methodget.
• ltform actionwelcome.php methodgetgt
• Nameltinput typetext namefname/gt
• Ageltinput typetext nameage/gt
• ltinput typesubmit/gt
• lt/formgt
• Clicks the submit button, the URL sent to the
  server could look like this
• http//localhost/welcome.php?fnameJackyage28

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PHP _POST Function

• The built-in _POST function is used to collect
  values from a form with methodpost.
• ltform actionwelcome.php methodpostgt
• Nameltinput typetext namefname/gt
• Ageltinput typetext nameage/gt
• ltinput typesubmit/gt
• lt/formgt
• Clicks the submit button, the URL sent to the
  server could look like this
• http//localhost/welcome.php

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PHP _GET and _POST Function

• Methodget should not be used when sending
  passwords or other sensitive information. It is
  possible to bookmark the page because the
  variables are displayed in the URL. The variable
  values cannot exceed 100 characters.
• Methodpost is invisible to others and has no
  limits on the amount of information to send. It
  is not possible to bookmark the page.

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PHP _REQUEST Function

• The built-in _REQUEST function contains the
  contents of both _GET, _POST, and _COOKIE. It
  can be used to collect form data sent with both
  the GET and POST methods.
• Welcome lt?php echo _REQUESTfname ?gt! ltbr /gt
• You are lt?php echo _REQUESTage ?gt years old.

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References

• W3schools.com Learn PHP http//www.w3schools.com
  /php/default.asp
• Wikipedia PHP http//en.wikipedia.org/wiki/PHP
• PHP A simple tutorial Manual
  http//php.net/manual/en/tutorial.php