php
DESCRIPTION
TRANSCRIPT
Introduction To PHP
Introduction to PHP• PHP Hypertext Preprocessor.
– Other Names : Personal Home Page, Professional Home Page
• Is a server side scripting language.– Capable of generating the HTML pages
• HTML generates the web page with the static text and images.
• However the need evolved for dynamic web based application, mostly involving database usage.
CLIENT
WEB SERVER
HTTP Request(url)
<HTML><?php PHP code ?></HTML>
Gets Page
<HTML><B>Hello</B></HTML>
Interprets the PHP codeServer response
Browser createsthe web page
Hello
Why PHP?• ..there are no. of server side scripting available like
ASP, SSJS, JSP…..• PHP involves
– simplicity in scripting (..generally using the database)– platform independence.
• PHP is – primarily designed for web applications– well optimized for the response times needed for web
applications
• Is an open source.
PHP Language features
• PHP language features such as control structures, operators, variable types, function declaration, class/object declaration are almost similar to any compiled or interpreted language such as C or C++.
PHP Data Type• Three basic data types
– Integer– Double– String
• More data types– Array– Object
• PHP is an untyped language – variables type can change on the fly.
PHP Block
• PHP code block is embedded within the <?php and ?> tags.
• When the server encounters the PHP tags it switches from the HTML to PHP mode.
• There are four different ways to embed the PHP code– <?php echo(“Some PHP code”); ?>– <? echo(“Some PHP code”); ?>– <SCRIPT Language=‘php’> echo(“Some PHP code”);
</SCRIPT>– <% echo(“Some PHP code”); %>
PHP Constants• ..values that never changes• Constants are defined in PHP by using the
define() function.– For e.g.
define(“NCST”, “National Centre for Software Technology”)
• defined() function says whether the constant exists or not.
PHP Variables
• The variables in PHP are declared by appending the $ sign to the variable name.– For e.g
$company = “NCST”;
$sum = 10.0;
• variable’s data type is changed by the value that is assigned to the variable.
• Type casting allows to change the data type explicitly.
PHP Variables (cont.)• Rich set of functions for working with
variable.– For e.g
• gettype, settype, isset, unset, is_int, intval etc etc
PHP Operators
• All the operators such as arithmetic, assignment, Comparison, and logical operators are similar to the operators in C and C++.
• In PHP the string concatenation operator is denoted by ‘.’.– For e.g.
• $name = “My name is”.$myname;
PHP Statements• IF statement
if (<condition>) {//php code goes here}
else {//php code goes here}
• Alternative Syntaxif(<condition>) :
//html code goes here
else ://html code goes here
endif;
PHP Statements (cont.)• For loop
for($i=0;$i < 10;$++i) {echo(“the value is :”. $i);
}– Alternative Syntax
for($i=0;$i < 10;$++i) :// html code goes here
endfor;
• While loop• Do-While loop
Functions
• Function declaration in PHPfunction my_func(<parameters>) {
//do something in the function
}– for e.g.
function sayHello() {echo(“<B>hello amrish<B><BR>”);
}
Functions (cont.)
• Assigning functions to the variables– for e.g
• $hello = “my_func”;• to invoke the function my_func() through the variable
$hello( );
• When an argument is to be passed by reference, an ampersand (&) is placed before the parameter name– for e.g.
my_func(&$my_refvar);
Arrays
• ..contains value set• each element has a value, data stored in the
element.• And has a key by which the element can be
referred to.
Initializing Arrays
• No of ways to initialize the array.– For e.g.
• $ncststaff[] = “amrish”;
$ncststaff[] = “murali”;
$ncststaff[] = “narayan”;• $ncststaff[123] = “amrish”;
$ncststaff[122] = “murali”;
$ncststaff[121] = “narayan”;• $ncststaff = array (“amrish”, “murali”, “narayan”);
– to change the indices of the array use => operator.
Accessing the Array Elements• The elements in the array can be accessed by
using the list and each constructs– for e.g
while(list($key,$value) = each(countries))echo(“$value<BR>\n”);
– current(<arrayname>) gives the current value being accessed. key(<arrayname>) gives the index of the current element that is being accessed.
– prev(<arrayname>) gives the previous element.– next(<arrayname>) gives the next element.
Accessing the Array Elements (cont.)– Array_walk(<arrayname>,<function_name>)
• function_name is the function that is written for every member of an array.
• For e.g$ncststaff = array (“amrish”, “murali”, “narayan”);
array_walk ($ncststaff, printstaff);
// function to print each element of the array
function printstaff($names) {
echo “<B>$names</B><BR>\n”;
}
Arrays (cont.)• $ncststaff = array (“dake” => array(“amrish”, “lakshana”, “venkat”),
“spc” => array(“narayan”, “murali”,“prasad”));
–creates a two dimensional array.• Sorting Functions
– sort() : sorts the elements in the numeric and alphabetical order.
– rsort() : sorts the elements in the reverse order.– asort() : sorts the elements in the array without
changing the indices.– ksort() : sorts the arrays by key.
Classes
• Class is a template of an object and includes the properties and methods that describe an object and behavior.
• Class in PHP is defined using class statement.
Classes (cont.)• For e.g<?
class company {
// define the properties
var $companyname;
// define the methods
function company($cname) {
$this->companyname = $cname;
}
function getnames($idcode) {
//return the name of the employee for the required idcode
}
}
?>
THANK YOU
Ayush Chugh(11csu036)
Ayushi Gupta(11csu037)