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Introduction to PHP
Introduction to PHP
Amrish V. Chaubal
Data & Knowledge Engineering Division
amrish@ncst.ernet.in
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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.
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WEB
SERVER
Introduction to PHP
Gets Page
<HTML>
<?php PHP code ?>
</HTML>
HTTP Request
(url)
Interprets the PHP code
Server response
CLIENT
Hello
<HTML>
<B>Hello</B>
</HTML>
Browser creates
the web page
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Introduction to PHP
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.
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Introduction to PHP
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++.
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Introduction to PHP
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.
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Introduction to PHP
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”); %>
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Introduction to PHP
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.
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Introduction to PHP
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.
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Introduction to PHP
PHP Variables (cont.)
• Rich set of functions for working with
variable.
– For e.g
• gettype, settype, isset, unset, is_int, intval etc etc
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Introduction to PHP
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;
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Introduction to PHP
PHP Statements
• IF statement
if (<condition>) {
//php code goes here
}
else {
//php code goes here
}
• Alternative Syntax
if(<condition>) :
//html code goes here
else :
//html code goes here
endif;
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Introduction to PHP
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
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Introduction to PHP
Functions
• Function declaration in PHP
function my_func(<parameters>) {
//do something in the function
}
– for e.g.
function sayHello() {
echo(“<B>hello amrish<B><BR>”);
}
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Introduction to PHP
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);
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Introduction to PHP
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.
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Introduction to PHP
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”;
• $ncststaff = array (“amrish”, “murali”, “narayan”);
– to change the indices of the array use => operator.
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Introduction to PHP
Accessing the Array Elements
• The elements in the array can be accessed by
using the list and each constructs
– for e.g
while(list($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.
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Introduction to PHP
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”;
}
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Introduction to PHP
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.
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Introduction to PHP
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.
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Classes (cont.)
Introduction to PHP
• 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
}
}
?>
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Introduction to PHP
PHP Richness
• PHP comes with myriad of options i.e.
supports several APIs and interfaces to other
programming tools such as
– Database connectivity.
– LDAP
– XML
– Mail protocols such as IMAP, SMTP
– Image functions
etc….
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Introduction to PHP
Support for Regular Expressions
• Not pretty things to look at and work with.
– E.g. ^.+@.+\\..+$
• PHP takes over the headache from the
programmers for explicitly coding for pattern
matching.
• Functions:
– ereg() and eregi()
– ereg_replace() & eregi_replace()
– split()
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Introduction to PHP
Image Generation & Manipulation
• PHP offers powerful set of functions for
generating and manipulating the images.
– Rendering regular geometric figures, modifying
images
– manipulate text, font and color and even the pixels
in the image.
• ….creating the images on the fly.
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Introduction to PHP
Image Generation & Manipulation
(cont.)
• PHP uses the GD library for the most of the image
functionality that it offers.
• GD library is used for generating the two-dimensional
graphics.
• PHP API’s provides us with functions to:
–
–
–
–
–
–
Create, delete, resize and modify images.
Draw basic geometric figures
Manipulate text and fonts
Manipulate colors
Interlace and manipulate pixels
Handle PostScript files
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Introduction to PHP
Mailing functions
• Sending E-Mails
– Mail()
• Used to send simple text messages.
• Depends on the local mail delivery system.
– Using SMTP
• Accepts the e-mail for every recipient and goes through trouble
of delivering the e-mails.
• Receiving E-Mails
– PHP works out well with the IMAP protocol.
– Rich set of support functions
• Imap_open, impa_delete, imap_close, imap_mail_copy,
imap_mail_move etc.
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Introduction to PHP
PHP-Database Connectivity
• Supports APIs for accessing large number of
databases.
• ODBC is a standard API for accessing a
database that has PHP support.
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Introduction to PHP
PHP-Database Connectivity
• Some of Oracle 8.x functions.
–
–
–
–
–
–
OCILogon
OCILogoff
OCIParse
OCIFetch; OCIFetchInto; OCIFetchStatement
OCIExecute
OCIFreeStatement
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Introduction to PHP
LDAP Support in PHP
• PHP provides LDAP API’s that allows the
programmers to create LDAP clients; by
providing transparent access to backend LDAP
directory servers.
– For e.g.
• Web based e-mail client.
• Telephone Directory.
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Introduction to PHP
XML Support in PHP
• PHP supports a set of functions that can be
used for writing PHP-based XML applications.
• These functions are used for parsing well
formed XML document.
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Introduction to PHP
References
• Professional PHP programming
– By Jesus Castagnetto, Chris Schollo et al
• www.phpbuilder.com
• www.php.net
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Introduction to PHP
THANK YOU
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