PHP

PHPThe Basic

Outline History of PHP

What is PHP?

What does PHP code look like?

Apache Server.

Syntax PHP code .

Anatomy of a PHP Script .

Data Types.

Variables.

Constants &Operators.

Control Structures.

Errors and Error Management .

History of PHPPHP (PHP: Hypertext Preprocessor) was created by Rasmus Lerdorf in 1994. It was initially developed for HTTP

usage logging and server-side form generation in Unix.

PHP 2 (1995) transformed the language into a Server-side embedded scripting language. Added database support, file uploads, variables, arrays, recursive functions, conditionals, iteration, regular expressions, etc.

PHP 3 (1998) added support for ODBC data sources, multiple platform support, email protocols (SNMP,IMAP), and new parser written by Zeev Suraski and Andi Gutmans .

PHP 4 (2000) became an independent component of the web server for added efficiency. The parser was renamed the Zend Engine. Many security features were added.

PHP 5 (2004) adds Zend Engine II with object oriented programming, robust XML support using the libxml2 library, SOAP extension for interoperability with Web Services, SQLite has been bundled with PHP

What is PHP?• Personal Homepage Tools/Form Interpreter

• PHP is a server-side scripting language a server-side scripting language designed specifically for the Web.

• An open source language

• PHP code can be embedded within an HTML page, which will be executed each time that page is visited.

• Filenames end with .php by convention

What is PHP? (cont’d)

Interpreted language, scripts are parsed at run-time rather than compiled beforehand

Executed on the server-side

Source-code not visible by client

‘View Source’ in browsers does not display the PHP code

Various built-in functions allow for fast development

Compatible with many popular databases

Why PHP ?

Open source / free software Cross platform to develop and deploy and to use Powerful, robust , scalable Web development specific Can be object oriented especially version 5 Large active developer community (20 millions websites Great documentation in many language www.php.net/docs.php

http://www.php.net/docs.php

What you need to start using PHP ?

• Installation • You will need

• Web server ( Apache )• PHP ( version 5.3)• Database ( MySQL 5 )• Text editor (Notepad) • Web browser (Firefox )• www.php.net/manual/ en/install.php

http://www.php.net/manual/

What does PHP code look like?

• Structurally similar to C/C++

• Supports procedural and object-oriented paradigm (to some degree)

• All PHP statements end with a semi-colon

• Each PHP script must be enclosed in the reserved PHP tag

<?php …?>

Syntax PHP code

• Standard Style : <?php …… ?>• Short Style: <? … ?>• Script Style: <SCRIPT LANGUAGE=‘php’> </SCRIPT>• ASP Style: <% echo “Hello World!”; %>

Echo• The PHP command ‘echo’ is used to output the

parameters passed to it• The typical usage for this is to send data to the

client’s web-browser• Syntax void echo (string arg1 [, string argn...]) • In practice, arguments are not passed in parentheses

since echo is a language construct rather than an actual function

Echo

<?phpecho “Welcome in PHP Page “;echo “my name is ali “;

?>

Variables in PHP• PHP variables must begin with a “$” sign• Case-sensitive ($Foo != $foo != $fOo)• Global and locally-scoped variables• Global variables can be used anywhere• Local variables restricted to a function or class• Certain variable names reserved by PHP• Form variables ($_POST, $_GET)• Server variables ($_SERVER)• Etc.

Variables in PHP

<?php $name ;?> <?php

$name = “ali” echo $name;?>

Variables

<?php$name = “Mohamed”;$age = 23;Echo “ My name is $name and I am $age

years old”;

?>

Variables <?php $name = “Ali"; // declaration ?> <html> <head> <title>A simple PHP document</title> </head> <body style = "font-size: 2em"> <p> <strong>  Welcome to PHP, <?php print( "$name" ); ?>! </strong> </p> </body> </html>

Variable variables

• That is variable whose name is contained in another variable.

Example :<?php $data = “a";$$data = “b"; echo $a; // echo ${'a'};?>

Single & Double Quotes

<?phpecho “ Hello world <br>”;echo ‘ Hello world’;?>

<?php$word = ‘ World’;echo ‘ Hello’ . $word . ‘<br>’;?>

Single & Double Quotes

General Example

• Notice how echo ‘5x5=$foo’ outputs $foo rather than replacing it with 25• Strings in single quotes (‘ ’) are not interpreted or evaluated by PHP • This is true for both variables and character escape-sequences (such as “\

n” or “\\”)

<?php$foo = 25; // Numerical variable$bar = “Hello”; // String variable

echo $bar; // Outputs Helloecho $foo,$bar; // Outputs 25Helloecho “5x5=”,$foo; // Outputs 5x5=25echo “5x5=$foo”; // Outputs 5x5=25echo ‘5x5=$foo’; // Outputs 5x5=$foo?>

Concatenation

• Use a period to join strings into one.

<?php

$string1=“Hello”;$string2=“PHP”;$string3=$string1 . “ ” . $string2;Print $string3;

?>

<?php

$string1=“Hello”;$string2=“PHP”;$string3=$string1 . “ ” . $string2;Print $string3;

?>

Hello PHPHello PHP

Anatomy of a PHP Script

• // or # for single line• /* */ for multiline• /***some info **this is type of comments */

Comments


• You cant have any whitespace between <? and php.

• You cant break apart keywords (e.g :whi le,func tion,fo r)

• You cant break apart varible names and function names (e.g:$var name,function f 2)

Whitespace


• Is simply a series of statements' enclosed between two braces :

{//some comand }

Code Block

Math operations<?php

$num1 = 10;$num2 =20;// additionecho $num1+$mum2 . ‘<br>’;//subtraction echo $num1 - $num2 . ‘<br>’; // multiplication

?>

<?php// multiplication echo $num1* $num2 . ‘<br>’;// division echo $num1/num2 . ‘<br>’ ;//increment $num1++;$num2--;echo $num1;

?>

Math operations

Arithmetic

• Arithmetic operators– Assignment operators

• Syntactical shortcuts• Before being assigned values, variables have value undef

• Constants– Named values– define function

Arithmetic Operators

• $a - $b // subtraction• $a * $b // multiplication• $a / $b // division• $a += 5 // $a = $a+5 Also works for *=

and /=

<?php$a=15;$b=30;$total=$a+$b;Print $total;Print “<p><h1>$total</h1>”;// total is 45

?>

<?php$a=15;$b=30;$total=$a+$b;Print $total;Print “<p><h1>$total</h1>”;// total is 45

?>

Arithmetic Operators <?php

$a =1; echo $a++; // output 1,$a is now equal to 2 echo ++$a; // output 3,$a is now equal to 3

echo --$a; // output 2,$a is now equal to 2 echo $a--; // output 2,$a is now equal to 1

?>

Arithmetic Operators

<?php

$a =(int)(‘test’); // $a==0 echo ++$a;

?>

Data type

Data type Description int,

integer Whole numbers (i.e., numbers without a decimal

point). float, double

Real numbers (i.e., numbers containing a decimal point).

string Text enclosed in either single ('') or double ("") quotes.

bool, Boolean

True or false.

array Group of elements of the same type. object Group of associated data and methods.

Resource An external data source. NULL No value.

Fig. 26.2 PHP data types.

Data type<?php

// declare a string, double and integer$testString = "3.5 seconds";$testDouble = 79.2; $testInteger = 12;

print( $testString ).”is a string<br/>”;print( $testDouble ).”is a double<br />”print( $testInteger ).”is an integer<br />”;

?>

Data type<?php // call function settype to convert variable // testString to different data types print( "$testString" ); settype( $testString, "double" ); print( " as a double is $testString <br />" ); print( "$testString" ); settype( $testString, "integer" ); print( " as an integer is $testString <br />" ); settype( $testString, "string" ); print( "Converting back to a string results in $testString <br /><br />" ); ?>

Data type

<?php $data = "98.6 degrees";print( "Now using type casting instead: <br />As a string - " . (string) $data . "<br />As a double - " . (double) $data . "<br />As an integer - " . (integer) $data );?>

Data type

<?php

$a = “ 12.4 abc” echo (int) $a;echo (double) ($a);echo (float) ($a);echo (string) ($a);

?>

Logic Operations Example Name Result

$a == $b Equal TRUE if $a is equal to $b after type juggling.

$a === $b Identical TRUE if $a is equal to $b, and they are of the same type.

$a != $b Not equal TRUE if $a is not equal to $b after type juggling.

$a <> $b Not equal TRUE if $a is not equal to $b after type juggling.

$a !== $b Not identical TRUE if $a is not equal to $b, or they are not of the same type.

$a < $b Less than TRUE if $a is strictly less than $b.

$a > $b Greater than TRUE if $a is strictly greater than $b.

$a <= $b Less than or equal to TRUE if $a is less than or equal to $b.

$a >= $b Greater than or equal to TRUE if $a is greater than or equal to $b.

Bitwise Operations

ExampleExample NameName ResultResult

A & B And Bits that are set in both A and B are set.

A | B Or Bits that are set in either A or B are set.

A ^ B Xor Bits that are set in A or B but not both are set.

~ A Not Bits that are set in A are not set, and vice versa.

A << B Shift leftShift the bits of A B steps to the

left (each step means "multiply by two")

A >> B Shift rightShift the bits of A B steps to the

right (each step means "divide by two")

Example cont..

<?php $x=13; $y=22; echo $x & $y;

?> <?php $x=77; $y=198; echo $x & $y;

?>

Example cont..<?php

$x=5; $y=11; echo $x | $y;

?><?php $x=12; $y=11; echo $x ^ $y;

?>

Example cont..<?php

$x=12; $y=10; echo $x & ~ $y;

?> <?php $x=8; $y=3; echo $x << $y;

?

Example cont..<?php

$x=12; $y=10; echo $x & ~ $y;

?> <?php $x=8; $y=3; echo $x << $y;

?

Example cont..

<?php $x=12; $y=4; echo $x << $y;

?> <?php

$x=8; $y=3;

echo $x >> $y;

?>

Referencing Operators

• We know the assignment operators work by value ,by

copy the value to other expression ,if the value in right

hand change the value in left is not change .

• Ex:$A =10;

$B =$a;

$B =20

Echo $a; // 10

Referencing Operators

• But we can change the value of variable $a by the

reference , that mena connect right hand to left hand ,

• Ex:

$A =10;

$B = &$a;

$B= 20;

Echo $a; // 20

Constant Value

Escaping the Character

• If the string has a set of double quotation marks that must remain visible, use the \ [backslash] before the quotation marks to ignore and display them.

Escaping the Character

<?php

$heading=“\”Computer Science\””;$heading1=@“Computer Science”;

Print $heading;Print $heading1;

?>

<?php

$heading=“\”Computer Science\””;$heading1=@“Computer Science”;

Print $heading;Print $heading1;

?>

“Computer Science”“Computer Science”

PHP Control Structures

• Control structures: are the structures within a language that

allow us to control the flow of execution through a program

or script.

• Grouped into conditional (branching) structures (e.G. If/else)

and repetition structures (e.G. While loops).

•

If ... Else...• If (condition)

{Statements;

}Else{

Statement;}

<?php$user = “John”;If($user==“John”){

Print “Hello John.”;}Else{

Print “You are not John.”;}?>

Hello John.

if/else if/else<?php

$foo = 4;

if ($foo == 0) {

echo ‘The variable foo is equal to 0’;

}

else if (($foo > 0) && ($foo <= 5)) {

echo ‘The variable foo is between 1 and 5’;

}

else {

echo ‘The variable foo is equal to ‘.$foo;

}

?>

Example

Example cont..

Example cont..

For Loops

• for ($varible = value ;condition;$value assigment ){

Statements;}

<?php$count=0;for($count = 0;$count <3,$count++){

Print “hello PHP. ”;?>

hello PHP. hello PHP. hello PHP.

Example (break)<?php/* example 1 */

for ($i = 1; $i <= 10; $i++) { echo $i;}

?>

Example (break)

<?php

for ($i = 1; ; $i++) { if ($i > 10) { break; } echo $i;}

?>

Example (break)<?php/* example 3 */

$i = 1;for (; ; ) { if ($i > 10) { break; } echo $i; $i++;}

/* example 4 */

for ($i = 1, $j = 0; $i <= 10; $j += $i, print $i, $i++);?>

Example (for)

<?php//this is a different way to use the 'for'

for($i = $x = $z = 1; $i <= 10;$i++,$x+=2,$z=&$p){ $p = $i + $x; print "\$i = $i , \$x = $x , \$z = $z <br />"; }

?>

Example – table <?php$brush_price = 5; echo "<table border=\"1\" align=\"center\">"; echo "<tr><th>Quantity</th>"; echo "<th>Price</th></tr>"; for ( $counter = 10; $counter <= 100; $counter += 10) { echo "<tr><td>"; echo $counter; echo "</td><td>"; echo $brush_price * $counter; echo "</td></tr>"; } echo "</table>";?>

Example (nested For)

<?php for($a=0;$a<10;$a++){ for($b=0;$b<10;$b++){ for($c=0;$c<10;$c++){ for($d=0;$d<10;$d++){ echo $a.$b.$c.$d.", "; } } } } ?>

Example (continue)

<?phpfor ($i = 0; $i < 5; ++$i) { if ($i == 2) continue print "$i\n";}?>

Example (for..if)<?php

$rows = 4;

echo '<table><tr>';

for($i = 0; $i < 10; $i++){ echo '<td>' . $i . '</td>'; if(($i + 1) % $rows == 0){ echo '</tr><tr>'; }}

echo '</tr></table>';

?>

While Loops

• While (condition){

Statements;}

<?php$count=0;While($count<3){

Print “hello PHP. ”;$count += 1;// $count = $count + 1;// or// $count++;

?>

hello PHP. hello PHP. hello PHP.

Example (while switch)<?php$i = 0;

while (++$i) { switch ($i) { case 5: echo "At 5<br />\n"; break 1; case 10: echo "At 10; quitting<br />\n"; break 2;

default: break; }}?>

Example (nested while)<?php$i = 0;

while ($i++ < 5) { echo "Outer<br />\n"; while (1) { echo " Middle<br />\n"; while (1) { echo " Inner<br />\n"; continue 3; } echo "This never gets output.<br />\n"; } echo "Neither does this.<br />\n";}?>

Do …While Loops

Do{

Statements;

}

While (condition);

<?php$count=0;Do{

Print “hello PHP. ”;$count += 1;

}While($count<3);?>

hello PHP.hello PHP.hello PHP.

Example (do..while)

<?php$i = 0;do { echo $i;} while ($i > 0);?>

Example (do..while)<?php

do { if ($i < 5) { echo "i is not big enough"; break; } $i *= $factor; if ($i < $minimum_limit) { break; } echo "i is ok";

/* process i */

} while (0);?>

Switch• switch(expression )

{ case value: break;.. default: break; }

<?php$count=0;switch($count){ case 0:

Print “hello PHP3. ”;break;case 1:

Print “hello PHP4. ”;break; default:

Print “hello PHP5. ”;break;

?> hello PHP3

Example <?php

if ($i == 0) { echo "i equals 0";} elseif ($i == 1) { echo "i equals 1";} elseif ($i == 2) { echo "i equals 2";}

switch ($i) { case 0: echo "i equals 0"; break; case 1: echo "i equals 1"; break; case 2: echo "i equals 2"; break;}?>

Example <?php

$total = 0;switch($i) { case 6: $total = 99; break; case 1: $total += 1; case 2: $total += 2; case 3: $total += 3; case 4: $total += 4; case 5: $total += 5;}?>

Errors & Error Management <?php

// Turn off all error reportingerror_reporting(0);

// Report simple running errorserror_reporting(E_ERROR | E_WARNING | E_PARSE);

// Reporting E_NOTICE can be good too (to report uninitialized// variables or catch variable name misspellings ...)error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);

// Report all errors except E_NOTICE// This is the default value set in php.inierror_reporting(E_ALL ^ E_NOTICE);

// Report all PHP errors (see changelog)error_reporting(E_ALL);

// Report all PHP errorserror_reporting(-1);

// Same as error_reporting(E_ALL);ini_set('error_reporting', E_ALL);

?>

Example 1<?php

$name = 'Elijah'; $yearBorn = 1975; $currentYear = 2005;$age = $currentYear - $yearBorn; print ("$name is $age years old.");

?>

Example 2 <?php

phpinfo();?>

<?phpprint("<font face=\"Arial\" color\"#FF0000\">Hello and welcome to my website.</font>");

?>

Example 3

<?php$hour = 11;

print $foo = ($hour < 12) ? "Good morning!" : "Good afternoon!";

?>

Example 4 (Isset)<?php

$value = 'Jesus';

// This is a simple if statement if( isset( $value ) ) { print $value; }

print '<br />';

// This is an alternative isset( $value ) AND print( $value );?>

Example 5 (Goto)<?php

goto a;echo 'Foo'; a:echo 'Bar';?>

<?phpfor($i=0,$j=50; $i<100; $i++) { while($j--) { if($j==17) goto end; } }echo "i = $i";end:echo 'j hit 17';?>

Documents

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