CSCTR 000

WHAT IS PHP
1. PHP is a server-side scripting language designed

specifically for the Web
2. PHP was conceived in 1994 and was originally

developed by Rasmus Lerdorf
3. PHP code is interpreted at the Web server and

generates HTML or other output
4. PHP is an Open Source product and it is licensed

under GPL.
5. PHP is a recursive acronym whihc stands for PHP

Hypertext Preprocessor.
WHY PHP
1. PHP is vary fast.
2.PHP supports many databases viz.,

MySQL,PostgreSQL, Oracle, Sybase, Informix etc.,
3.It can connect to any database that provides

driver for Open DataBase Connectivity.
4. PHP has lots of extension like generating

images, generating pdf, mail , RSS, Web Services
5. PHP is cross platform.
6. It is easy to learn
BASIC SYNTAX
1. Can be embedded in HTML

<html>
<head><title>First Exercise</tilte></head>
<?php
echo "hello";
?>
<body>
World
</body>
</html>
TAGS
1. <? echo "hi how are you?"; ?>
2.<?php eho "Hello World"; ?>
3. <script langage="php"
echo "Hello World";
</script>
4. <% echo "Hello World"; %>

enable asp_tags in configuration file
DELIMITER
1. semicolon is used as instruction separator in PHP

COMMENTS
1. A double slash or # is used for single line comment
<?php
echo "This is one line comment"; //The part of
comment
echo "This is also a comment" ; #This is also part of
comment
?>
2. Multi line comment done in C or C++ way

<?php
/*
More than one line
is now commented
*/
?>
DATA TYPES
1. integer
2. Floating-point numbers
3. string
4. array
5. object
INTEGER
Integers can be assigned any of the following values:
$a = 120; # decimal number
$a = -123; # a negative number
$a = 0123; # octal number
$a = 0x12; # hexadecimal number

FLOATING POINT NUMBERS
Floating point numbers can be assigned any of the

following values:
$a = 1.234;
$a = 1.2e3;
STRING
Strings can be represented using eihter double quotes

or single quotes.
Assining value to a string variable.
$str = "This is a string";

ESCAPE SEQUENCES
\n linefeed
\r carriage return
\t horizontal tab
ARRAYS
1. PHP supports both indexed and key/value pair

array.
2. Create an array by setting values for each element

of an array
$arr[0]=1;
$arr[1]="hello";
$arr[2]="apple";
$arr[]=”flower”;
3. You can create an array using either list() or

array() functions.
OBJECTS
1. Objects are instances of classes.
class a
{
var $var="hello";
function echo_hello()
{
echo $this->var;
}
}
$a=new a();
TYPE CASTING
1. Type casting in PHP is done as below.

$a = 10; // $a is an integer
$b = (double) $b; //$b is double
2. The casts allowed are:

(int), (integer) - cast to integer
(real), (double), (float) - cast to double
(string) - cast to string
(array) - cast to array
(object) - cast to object
VARIABLES
1. Placeholder with name
2. The first letter of the varible name should be a

letter or underscore followed by letters, numbers and
underscores.
3. $_a="this a varible"; # valid

$b=100; # valid
$2c="test"; # invalid, variable name
starts with a digit
VARIABLE VARIABLES
1. A variable variable takes the value of a varible and

assigns it as the name of a varible
$a="hello";
$$a="this is a test";
2. echo $a $hello;
CONSTANTS
1. Constants are defined using the keyword define

define('HELLO',"hello”);
echo HELLO;
PREDEFINED VARIABLES
1. APACHE VARIABLES
2. PHP VARIABLES
APACHE VARIABLES
REQUEST_METHOD
GET, HEAD, POST, PUT.
QUERY_STRING
The query string, if any, via which the page was
accessed.
DOCUMENT_ROOT
The document root directory under which the
current script is executing, as defined in the server's
configuration file.
HTTP_USER_AGENT
Contents of the User_Agent
PHP VARIABLES
PHP_SELF
The filename of the currently executing script.
(not for cli)
$_COOKIE
An associative array of variables passed to the
current script via HTTP cookies.
$_GET
current script via the HTTP GET method.
$_POST
current script via the HTTP POST method.
$_FILES
An associative array of variables containing
information about files uploaded via the HTTP
SCOPE OF VARIABLE
1. Visibility or the life of the variable
2. PHP variables only a have single scope. This single

scope spans included and required files also.
$a=10;
include "footer.inc";
3. variables declared inside user-defined functions

have local scope
GLOBAL SCOPE
$visible=10;
function test()
{
print $visible;
}
test();
PHP will not look at the global variable when it

encounters an variable inside a fucntion.
OVERRIDE LOCAL SCOPE
$visible=10;
function test()
{
global $visible;
print $visible;
}
test();
function test()
{
print $GLOBALS['visible'];
}
test();
OPERATORS
1. Arithmetic Operators
2. String Operators
3. Assignment Operators
4. Comparison Operators
5. Logical Operators
6. Bitwise Operators
7. The Ternary Operator
8. The Error Control Operator
9. The Execution Operator
BITWISE OPERATORS
bitwise AND &
bitwise OR |
bitwise NOT ~
bitwise XOR ^
left shift <<
right shift >>

ARITHMETIC OPERATORS
'+' - Addition
'-' - Subtraction
'* - Multipication
'/' - Division
'%' - Modulus
COMPARISON OPERATORS
== equals
=== identical
!= not equal
<> not equal
< less than
> greater than
<= less than or equal to
>= greater than or equal to
LOGICAL OPERATORS
NOT !
AND &&
OR ||
BITWISE OPERATORS
bitwise AND &
bitwise OR |
bitwise NOT ~
bitwise XOR ^
left shift <<
right shift >>

String Operators
The dot operator is used as concatenation.
$a="hello"."world";
Assignment Operators
The '=' is used as the assignment operator.
$a+=5;
which is equivalent to
$a=$a+5;
The Ternary Operator

This operator, ?:, takes the form
condition ? value if true : value if false
The error control operator
@ - can be used in front of any expression
The Execution Operator

a pair of backticks (``)
PHP will attempt to execute whatever is contained
between the backticks as a system command.
VARIABLE FUNCTIONS
1. gettype(parameter)
2. settype(variable name, datatype as string)
3. is_int()
4. is_float($a)
5. is_string($a)
6. is_object($a)
7. int isset($a)
8. int isset($a)
9. int empty($a)
10. intval($a)
11. doubleval($a)
12. strval($a)
CONTROL STRUCTURES
To control the flow of execution
1. If-ElseIf-Else
2. while
3. Switch
4. break
5. continue
6. exit
7. for
8. foreach
9. include statements
IF-ELSEIF-ELSE
if ($a>$b)
{
echo "a is bigger than b";
}
elseif($b>$a)
{
echo "b is bigger than a";
}
else
{
echo "a and b are equal";
}
SWITCH
switch($gender)
{
case 'male' :
echo "gender is male";
break;
case 'female' :
echo "gender is female";
break;
default :
echo "none of the above";
break;
}
WHILE
$i=0;
while($i<10)
{
echo $i;
$i++;
}
$a=10;
do
{
echo $a;
$a--;
} while ($a > 1 );
BREAK
$a=0;
while($a<10)
{
$a++;
if($a==5)
{
break;
}
echo $a;
}
CONTINUE
$a=0;
while($a<10)
{
$a++;
if($a==5)
{
continue;
}
echo $a;
}
EXIT
$a=0;
while($a<10)
{
$a++;
if($a==5)
{
exit;
}
echo $a;
}
FOR
for ($i=0; $i<10; $i++)

{
echo $i;
}
FOREACH
$arr=array(1,2,3,45);
foreach($arr as $a)
{
echo $a;
}
$a = array (
"lab" => “192.168.1.10”,
"office" =>"192.168.1.12",
"gateway" => "192.168.1.1",
3 => "hosts"
);
foreach($arr as $key=>$value)
{
echo "Key : $key; Value: $value\n";
}
INCLUDE STATEMENTS
1. require (“connect.inc”);
2. include (“connect.inc”);
3. include_once(“connect.inc”);
4. require_once (“connect.inc”);
FUNCTIONS
1. A function is a self-contained module of code that

prescribes a calling interface, performs some task,
and optionally returns a result.
2.To write a function in php the 'function' keyword

followed by the name of the function and then list of
arguments passed to the function inside braces.
Optionally the function may return some value.
BASIC FUNCTION STRUCTURE
function name_of_function(arg1,arg2,......)
{
any valid php code

return anyvalue;
}
FUNCTION NAME
1. Function cannot have the same name as an

existing function.
2. Function name can only contain letters, digits, and

underscores
3. Function name cannot begin with a digit

FUNCTION DEFINITION
1. function square()
{
$a=5;
$b=$a*$a;
echo $b;
}
2. function square($a)
{
$b=$a*$a;
return $b;
}
FUNCTION CALL
1. square();
2. $c=square(5);
echo $c;
3. echo square(5);
SCOPE OF VARIABLE
1. A variable defined inside a function is visible only
within that i.e., the scope of the variable is local inside
a function.
2. To create a global variable inside a function use the

keyword 'global' before the variable.
function echo_var()
{
global $var = "globally scoped";
echo "The value of var = ".$var."\n";
}
echo "The value of var outside= ".$var."\n";

RECURSIVE FUNCTION
1. A recursive function is one that calls itself.
Recursive functions are slower and use more memory
than iteration, so you should use iteration wherever
possible.
function factorial($n)
{
if($n==1)
return 1;
else
return $n*factorial($n-1);
}
echo factorial(5);
PASS BY REFERENCE
If you wish to pass a variable by reference to a

function which does not do this by default, you may
prepend an ampersand to the argument name in the
function call:
$a=5;
echo factorial(&$a);
echo $a;
ARRAYS
Arrays actually act like both hash tables

(associative arrays) and indexed arrays
(vectors).
TYPE OF ARRAYS
This type array is supported in most of the programming
languages. Arrays can be created by assinging values to
each elements of the array using the index.
$arr[0]="flower";
$arr[1]="fruit";
$arr[2]="numbers";
In PHP, the indices start at zero by default. However, we can

instruct array( ) to use a different index using the =>
syntax:
$arr = array(1 => 'flower', 'fruit', 'vegetable', 'cereals');
Alternatively arrays can be created using the function array.

$arr=array("flower","fruit","numbers");
ACCESSING ARRAY ELEMENTS
The array elements can be accessed using their

index.
echo $arr[0];
A For loop can be used to access the elements of an

array
for($i=0; $i<3; $i++)
{
echo $arr[$i];
}
ASSOCIATIVE ARRAY
1. An associative array is an array which has its index

as key.
2. The key can be in any form either a string or

number etc.,
3. The associative array is created as the same a

scalar array is created.
4. The value of keys should be unique.

$fruits = array('red' => 'Apples', 'yellow' =>
'Bananas', 'beige' => 'Cantaloupes', 'brown' =>
'Dates');
while(list($key,$val)=each($fruits))
{
echo "key: $key; Value: $val\n";
}
MULTIDIMENSIONAL ARRAY
$employees = array(
array( "ram","manager", 10000 ),
array( "sam", "executive", 15000 ),
array( "raj", "vp", 40000 )
);
ARRAY FUNCTION
1. Sorting Arrays
sort($arr);
2. An associative array can be sorted in ascending

order, using asort() or ksort().
asort is used to sort the associative array based on

the value of the each item.
ksort is used to sort the array based on the keys.
3. Sorting Multidimensional Arrays is done using usort

usort(array array,function cmp_function)
ARRAY FUNCTIONS
1. array_reverse is a function used to reverse the
order of an array
2. $pwd=file("/etc/dhcp3/dhcp.conf");
print_r($pwd)
3. To modify every element in an array in the same
way use array_walk(array,function name);
function mul($a)
{
$a*=2;
print $a;
}
4. array_count_values($array), this function counts
how many times each unique value occurs in the
array $array. Creates an associative array with key as
array elements and value as no of occurances.

CSCTR 000

Uploaded by

Copyright:

Available Formats

CSCTR 000

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

CSCTR 000

Uploaded by

Copyright:

Available Formats

WHAT IS PHP

1. PHP is a server-side scripting language designed

2. PHP was conceived in 1994 and was originally

3. PHP code is interpreted at the Web server and

4. PHP is an Open Source product and it is licensed

5. PHP is a recursive acronym whihc stands for PHP

2.PHP supports many databases viz.,

3.It can connect to any database that provides

4. PHP has lots of extension like generating

5. PHP is cross platform.

1. Can be embedded in HTML

1. <? echo "hi how are you?"; ?>

2.<?php eho "Hello World"; ?>

4. <% echo "Hello World"; %>

1. semicolon is used as instruction separator in PHP

2. Multi line comment done in C or C++ way

Integers can be assigned any of the following values:

$a = 120; # decimal number

$a = -123; # a negative number

$a = 0123; # octal number

$a = 0x12; # hexadecimal number

Floating point numbers can be assigned any of the

Strings can be represented using eihter double quotes

Assining value to a string variable.

$str = "This is a string";

1. PHP supports both indexed and key/value pair

2. Create an array by setting values for each element

3. You can create an array using either list() or

1. Objects are instances of classes.

1. Type casting in PHP is done as below.

2. The casts allowed are:

1. Placeholder with name

2. The first letter of the varible name should be a

3. $_a="this a varible"; # valid

1. A variable variable takes the value of a varible and

1. Constants are defined using the keyword define

1. Visibility or the life of the variable

2. PHP variables only a have single scope. This single

3. variables declared inside user-defined functions

PHP will not look at the global variable when it

bitwise AND &

left shift <<

right shift >>

bitwise AND &

left shift <<

right shift >>

The Ternary Operator

The Execution Operator

To control the flow of execution

for ($i=0; $i<10; $i++)

1. A function is a self-contained module of code that

2.To write a function in php the 'function' keyword

any valid php code

1. Function cannot have the same name as an

2. Function name can only contain letters, digits, and

3. Function name cannot begin with a digit

2. To create a global variable inside a function use the

echo "The value of var outside= ".$var."\n";