OpenGurukul : Language : PHP

PHP

By
OpenGurukul Team

www.opengurukul.com

Chapter 1
Introduction to php

www.opengurukul.com 2

Introduction to web application
What is Web Application?
Components of Web Application
-Presentation
-Processing
Uses of PhP
- Server Side Scripting
- Command Line Scripting
- Writing Desktop Applications

Introduction to PHP
Basic PHP Syntax
<?php ?>
Example of php program
<html><body>
<?php echo “Hello world”; ?>
</body></html>
Comments in php
<html><body>
<?php //This is a comment
/*This is a comment block */?>
</body></html>

Chapter 2

Php data types


Php data Types
A data type refers to the type of data a variable can store.
8 different type of data types are:
integer numbers
floating point numbers
strings
booleans
arrays
objects
resouces
null

Integers
An integer is a number of the set Z = {..., -2, -1, 0, 1, 2, ...}.
Example
<?php
$a = 1234; // decimal number
$a = -123; // a negative number
$a = 0123; // octal number (equivalent to 83 decimal)
$a = 0x1A; // hexadecimal number (equivalent to 26 decimal)
?>
Integer Data type can be divided into two types – Octal, Hexadecimal,
Decimal

Floating point numbers
Floating point numbers are those data types which can store decimal values
Example
<?php
$a = 1.234;
$b = 1.2e3;
$c = 7E-10;
?>


Strings
A string is series of characters.
Example
<?php
$str=”Hello world”;
echo $str;
?>
Output: Hello World


Booleans
This variable must be true or false
Example
<? php
$foo = True;
// assign the value TRUE to $foo
?>


Arrays
An array is a variable that holds a group of values.
Referencing array elements is done like this:
Example
$arrayName[index];
assign a value to an array position:
$listing[0] = "first item";
$listing[1] = "second item";
$listing[2] = "third item";


Object
An object is a data type that allows echo "This is example of object data
for the storage of not only data type.";
but also information on how to
process that data. }

Example: }

<?php $bar = new foo;

class foo $bar->do_foo();

{ ?>

function do_foo() Output :This is example of object
data type.
{


Resources and Null
Resources
Resources are really integers under the surface. Their main benefit is that
they're garbage collected when no longer in use. When the last reference
to a resource value goes away, the extension that created the resource is
called to free any memory, close any connection, etc. for that resource:
Null
The NULL value represents a variable that has no value
<?php
$var = NULL;
?>


Type Casting
PHP will automatically convert data types as necessary across the board
Example
<?php
$mystring = "wombat";
$myinteger = (integer)$mystring
?>
At first, $mystring contains a string.
However, we type cast it to be an integer, so PHP will convert it to an
integer, and place the result into $myinteger


Type juggling
if we add two integer variables then the result is integer type
but if we add one integer and one float type variable then the result is float
type because float type has a higher precedence than integer.
Example
<?php
$foo = "0"; // $foo is string (ASCII 48)
$foo += 2; // $foo is now an integer (2)
$foo = $foo + 1.3; // $foo is now a float (3.3)
$foo = 5 + "10 Little Piggies"; // $foo is integer (15)
$foo = 5 + "10 Small Pigs"; // $foo is integer (15)
?>

Chapter 3

Variables


variables
Variables are used for storing values

When a variable is declared, it can be used over and over again in your
script.

All variables in PHP start with a $ sign symbol.

The variable name is case-sensitive.
Ex-$var_name = value;


PHP-loosely typed language
Example
<?php
$txt="Hello World!";
$x=16;
?>
a variable does not need to be declared before adding a value to it.
It automatically converts the variable to the correct data type, depending on
its value.


Variable scope
Example
<?php
$a=1; /* global scope*/
function test()
{
echo $a;
} /* reference to local scope variable*/}
test();
?>
output:It will not produce any output

Global keyword
Example<?php
$a=1;
$b=2;
function sum()
{
global $a, $b;
$b = $a + $b;
}
Sum();
echo $b; www.opengurukul.com 20
?> output: 3

Variables variables
Example
<?php
$a=”hello”;
$$a=”world”;
echo "$a ${$a}";
?>
Here $a is hello then $hello is world so final out put is hello world


Chapter 4

Constants And
Expressions


Constants
Constants just as variables are used to store information.

difference between constants and variables is that constant value can not be
changed in the process of running program.

A constant is case-sensitive by default

define a constant by using the define()-function or the const keyword
outside a class definition.


Define function
Example
<?php
define("PASSWORD","admin"); // first we define a constant PASSWORD
echo (PASSWORD); // will display value of PASSWORD
constant, i.e. admin
echo constant("PASSWORD"); // will also display admin
echo "PASSWORD"; // will display PASSWORD
?>


Const keyword
Example
<?php

const CONSTANT = 'Hello World'; // Works as of PHP 5.3.0

echo CONSTANT;
?>


Magic Constants
PHP provides a large number of predefined constants to any script which it
runs.
__LINE__:The current line number of the file
__FILE__:The full path and filename of the file
__DIR__:The directory of the file
__FUNCTION__:The function name(case-sensitive)
__CLASS__:The class name(case-sensitive)
__METHOD__:The class method name(case-sensitive)
__NAMESPACE__:The name of the current namespace (case-sensitive)


Expressions
Example
$a = “5"
you're assigning '5' into $a. '5', obviously, has the value 5, or in other words
'5' is an expression with the value of 5 (in this case, '5' is an integer
constant).
After this assignment, you'd expect $a's value to be 5 as well.
So if you wrote $b = $a, you'd expect it to behave just as if you wrote $b = 5.
In other words.
$a is an expression with the value of 5 as well.


Chapter 5

Operators


Operators
Operators are used to operate on values.

Different types of operators we are using in php.
i.Arithmetic Operators
ii.Assignment Operators
iii.Comparison Operators
iv.Logical Operators


Arithmetic Operators
Operator Description Example Result
+ Addition x=2,x+2 4
- Subtraction x=2,5-x 3
* Multiplication x=4 20
x*5
/ Division 15/5 3
5/2 2.5
% Modulus (division 5%2 1
remainder) 10%8 2
10%2 0
++ Increment x=5 x=6
x++
-- Decrement x=5 x=4
x--

Assignment Operators

Operator Example Is The Same As
= x=y x=y
+= x+=y x=x+y
-= x-=y x=x-y
*= x*=y x=x*y
/= x/=y x=x/y
.= x.=y x=x.y
%= x%=y x=x%y


Comparision Operators

Operator Description Example
== is equal to 5==8 returns
false
!= is not equal 5!=8 returns true
<> is not equal 5<>8 returns true
> is greater than 5>8 returns false
< is less than 5<8 returns true
>= is greater than or 5>=8 returns
equal to false
<= is less than or 5<=8 returns true
equal to


Logical Operators

Operator Description Example
&& and x=6
y=3

(x < 10 && y > 1) returns true
|| or x=6
y=3

(x==5 || y==5) returns false
! not x=6
y=3

!(x==y) returns true

Operator precedence
Example
1 + 5 * 3=16 and not 18

because ("*") operator has a higher precedence than the ("+") operator
Parentheses may be used to force precedence, if necessary.

(1 + 5) * 3=18

If operator precedence is equal, left to right associativity is used.


Chapter 6

Control Structure


Conditional Statements
Conditional statements are used to perform different actions based on
different conditions.

PhP have the following conditional statements
if statement
if else statement
if elseif else statement
switch statement


If statement
Syntax Example
if (condition) <?php

code to be executed if condition is true; $a=2;

if($a==2)
else
echo “It is two”;
code to be executed if condition is false;
?>

output::It is two


If else Statement
Syntax Example
<?php
if (condition)
$a=2;
code to be executed if condition is
true; $b=3;

if($b>$a)
else
{
code to be executed if condition is
echo “b is greater”;
false;
}

else

{

echo “a is greater”;

}

?> output::b is greater

The if...else if....else Statement
Use the if....elseif...else statement to select one of several blocks of code to
be executed.
Syntax
if (condition)
code to be executed if condition is true;
elseif (condition)
code to be executed if condition is true;
else
code to be executed if condition is false;


if..else if..else statement
Example elseif ($a == $b)
<?php {
$a=3; echo "a is equal to b";
$b=4; }
if ($a > $b) else
{ {
echo "a is bigger than b"; echo "a is smaller than b";
} }
?>
output: a is smaller than b

Switch statement
Use the switch statement to select one of many blocks of code to be
executed.
Syntax
switch (n){
case label1:

code to be executed if n=label1;
break;
case label2:

code to be executed if n=label2;
break;

default:
code to be executed if n is different from both label1 and label2;}

Switch statement
Example case 3:

<?php echo "Number 3";

$x=1; break;

switch ($x) default:

{ echo "No number between 1 and 3";

case 1: }

echo "Number 1"; ?>

break; output:Number 1

case 2:
echo "Number 2";

break;

looping
A loop is simply a block of code that executes multiple times.
The following loops are available in php
- while statement
- do while statement
- for statement
- foreach statement


The while loop
This loop executes a block of code Example
while a condition is true.
<?php
Syntax
$i=1;
while (condition)
while($i<=5)
{
{
code to be executed;
echo $i;
}
$i++;
}
?>
output:12345

The do...while Statement
The loop will always execute the block of Example
code once,then check the condition,
and repeat the loop while the <?php
condition is true.
$i=1;
Syntax
do
do
{
{

$i++;

} echo $i;
while (condition); }
while ($i<=5);
?>
output:123456

The for statement
The loop is used when you know in Example
advance how many times the
<?php
script should run.
for ($i=1; $i<=5; $i++)
Syntax
{
for (init; condition; increment)
echo $i ;
{

code to be executed; }

} ?>

output:12345


The foreach Loop
The foreach loop is used to loop through arrays.
Syntax
foreach ($array as $value)
{
}
For every loop iteration, the value of the current array element is assigned to
$value (and the array pointer is moved by one) - so on the next loop
iteration, you'll be looking at the next array value.


Chapter 7

Array


Array
Array is a special type of variable which stores similar types of data.
There are 3 types of array
Numeric array:An array with a numeric index
Associative array:An array where each ID key is associated with a
value
Multidimensional array:An array containing one or more arrays


Numeric Arrays
There are two methods to create a numeric array.
i.In the following example the index are automatically assigned (the index starts at 0):
Ex-$cars=array("Saab","Volvo","BMW","Toyota");
ii.In the following example we assign the index manually:
$cars[0]="Saab";
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";


Associative Arrays
Example1
In this example we use an array to assign ages to the different persons
$ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);
Example2
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";


Multidimensional Arrays
Example
<?php

$families = array(

"Griffin"=>array ("Peter","Lois","Megan" ),

"Quagmire"=>array("Glenn" ),

"Brown"=>array ("Cleveland", "Loretta", "Junior" ));

?>

Output
Array([Griffin] => Array([0] => Peter [1] => Lois [2] => Megan)

[Quagmire] => Array([0] => Glenn )

[Brown] => Array([0] => Cleveland [1] => Loretta [2] => Junior ))

Array Functions
List()
The list() function is used to assign values to a list of variables in one operation.

Syntax
list(var1,var2...)

Example
<?php $my_array = array("Dog","Cat","Horse");
list($a, $b, $c) = $my_array;
echo "I have several animals, a $a, a $b and a $c.";
?>

output:I have several animals, a Dog, a Cat and a Horse.

count()
The count() function counts the elements of an array, or the properties of an object.

Syntax
count(array,mode)
Example
<?php $people = array("Peter", "Joe", "Glenn", "Cleveland");
$result = count($people);
echo $result;
?>

output: 4


array_sum()
The array_sum() function returns the sum of all the values in the array.

Syntax
array_sum(array)
Example
<?php
$a=array(0=>"5",1=>"15",2=>"25");
echo array_sum($a);
?>

output: 45


Many other functions are there

array_pop() - Pop the element off the end of array
array_push - Push one or more elements onto the end of array
sort - Sort an array
asort - Sort an array and maintain index association
arsort - Sort an array in reverse order and maintain index association
ksort - Sort an array by key
krsort - Sort an array by key in reverse order
print_r - Display all the readable information about the array


Chapter 8

PHP Forms and User
Inputs


Html form example
Example
The example below contains an HTML form with two input fields and a submit button:
html_form.php
<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="fname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>

Collecting data from a form
When a user fills out the form above and click on the submit button, the form
data is sent to a PHP file, called "welcome.php":
"welcome.php" looks like this:
File: welcome.php
<html><body>
Welcome <?php echo $_POST["fname"]; ?>!<br />
You are <?php echo $_POST["age"]; ?> years old.
</body></html>
ouput: Welcome John!
You are 28 years old.

Php $_GET function
It is used to collect values from a form.

Information sent from a form is visible to everyone (it will be
displayed in the browser's address bar)

Not fit for sending passwords or other sensitive information!

Not suitable for very large variable values.(not exceeding 2000
characters)


$_GET function
Example
<form action="welcome.php" method="get">


</form>

URL looks like this:
http://www.w3schools.com/welcome.php?fname=Peter&age=37
In welcome.php
Welcome <?php echo $_GET["fname"]; ?>.<br />
You are <?php echo $_GET["age"]; ?> years old!

Php $_POST function
It is also used to collect values from a form.
Information sent from a form is invisible to others and has no limits on
the amount of information to send.
here is an 8 Mb max size for the POST method, by default .
Size can be changed by setting the post_max_size in the php.ini file.
It is fit for the password or any other sensitive information


$_POST function
Example
<form action="welcome.php" method="post">
</form>
The URL will look like this:
http://www.w3schools.com/welcome.php
In welcome.php
Welcome <?php echo $_POST["fname"]; ?>!<br />
www.opengurukul.com
You are <?php echo $_POST["age"]; ?> years old. 63

Php $_REQUEST function
This 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.
Example
Welcome <?php echo $_REQUEST["fname"]; ?>!<br />
You are <?php echo $_REQUEST["age"]; ?> years old.


Chapter 9

String Handling


String Variables
A string variable is used to store and manipulate text.
Example
<?php
$txt="Hello World";
echo $txt;
?>

output: Hello World


String Literal Syntax
A string literal can be specified in four different ways:
single quoted
double quoted
heredoc syntax
Example of single quoted:
<?php
$str='Hello World';
?>


Example of double quote
<?php $str=”hello world”; ?>

Example of heredoc
Heredoc is a robust way to create string in PHP with more lines but without using
quotations.

<?php
$str = <<<DEMO
This is a demo message with heredoc.
DEMO;
echo $str; ?>
output: This is a demo message with heredoc.

The concatenation operator
The concatenation operator (.) is used to put two string values together.
Example
<?php
$txt1="Hello World!";
$txt2="What a nice day!";
echo $txt1 . " " . $txt2;
?>
output: Hello World! What a nice day!


String Function
Strlen()
The strlen() function is used to return the length of a string.
Syntax
int strlen ( string $string )
Example
<?php
$str = 'abcdef';
echo strlen($str); // 6
$str = ' ab cd ';
echo strlen($str); // 7
?>

str_replace()
It replaces some characters with some other characters in a string.

Syntax
str_replace(find,replace,string,count)

Example
<?php
$arr = array("blue","red","green","yellow");
print_r(str_replace("red","pink",$arr,$i));
echo "Replacements: $i";
?>
output:Array([0] => blue [1] => pink [2] => green [3] => yellow)
Replacements: 1 www.opengurukul.com 71

strrev()
The strrev() function reverses a string.
Syntax
strrev(string)
Example
<?php
echo strrev("Hello World!");
?>

output : !dlroW olleH


Strrpos()
The strrpos() function finds the position of the last occurrence of a string
inside another string.
Syntax
strrpos(string,find,start)
Example
<?php
echo strrpos("Hello world!","wo");
?>
output: 6


Explode()
The explode() function breaks a string into an array.

Syntax
explode(separator,string,limit)

Example
<?php

$str = "Hello world. It's a beautiful day.";
print_r (explode(" ",$str));

?>

output:
Array([0] => Hello [1] => world. [2] => It's [3] => a [4] => beautiful [5] => day.)


Chapter 10

Function


Function
A function is a block of code that performs a specific task. It has a
name and it is reusable.
There are two types of functions
-Built-in functions
-User defined functions


User defined function
Functions those are defined by user Example
according to user requirements. <?php
Syntax function writeName()
function functionName() {

{ echo "Kai Jim Refsnes";

code to be executed; }

} echo "My name is ";
writeName();
?>

output: My name is Kai Jim Refsnes


Function Arguments
Information may be passed to echo "My sister's name is ";
functions via the argument list, writeName("Hege");
which is a comma-delimited list of
expressions. ?>
output:My name is Kai Jim Refsnes.
Example
My sister's name is Hege Refsnes.
<?php
function writeName($fname)

{
echo $fname . " Refsnes.<br />";

}
echo "My name is ";

writeName("Kai Jim");

Pass by value vs. Pass by
reference
Ex-pass by value Ex-pass by reference
<?php <?php

function pass_by_value($param) function_by_reference(&$param)

{ {

push_array($param, 4, 5); push_array($param, 4, 5);

} }

$ar = array(1,2,3); $ar = array(1,2,3);

pass_by_value($ar); pass_by_reference($ar);

foreach ($ar as $elem) foreach ($ar as $elem)

{ {

print "<br>$elem"; print "<br>$elem";

} }

?> output:1, 2, 3 ?> output: 1, 2, 3, 4, 5.

Return values
To let a function return a value, use the return statement .
Example
<?php
function add($x,$y)
{
$total=$x+$y;
return $total;
}
echo "1 + 16 = " . add(1,16);
?>
ouput:1 + 16 = 17 www.opengurukul.com 80

Built-in function
Date()
The PHP date() function is used to format a time and/or date.

Syntax
date(format,timestamp)
Example
<?php echo date("Y/m/d") . "<br />";

echo date("Y.m.d") . "<br />";
echo date("Y-m-d"); ?>

output:2009/05/11
2009.05.11

2009-05-11 www.opengurukul.com 81

mktime()
The mktime() function returns the Unix timestamp for a date.

Syntax
mktime(hour,minute,second,month,day,year,is_dst)
Example
<?php
$tomorrow = mktime(0,0,0,date("m"),date("d")+1,date("Y"));

echo "Tomorrow is ".date("Y/m/d", $tomorrow);
?>
output:Tomorrow is 2009/05/12


include()
You can insert the content of one PHP file into another PHP file before the server
executes it

Example
<html>
<body>

<?php include("header.php"); ?>
<h1>Welcome to my home page!</h1>
<p>Some text.</p>

</body>
</html>


Require()
It is identical as the include function

Example()
<?php
require("wrongFile.php");
echo "Hello World!";
?>


Include vs Require
Include Require
Generates warning if file not found Gives fatal error if file not found
Script will continue execution Script will stop


require_once() & include_once()
include_once() and require_once() function is used to include a file only
once in a page.
Example
<?php
require_once(“header.php");
include_once(“header.php");
?>


Chapter 11

cookies


cookie
A cookie is often used to identify a user.

A cookie is a small file that the server embeds on the user's computer.

It is used for an origin website to send state information to a user's browser
and for the browser to return the state information to the origin site


Creating Cookie
The setcookie() function is used to set a cookie.
Syntax
setcookie(name, value, expire, path, domain);
Example
<?php
setcookie("user", "Alex Porter", time()+3600);
?>


Retrieving Cookie Value
The PHP $_COOKIE variable is used to retrieve a cookie value.
Example
<?php

echo $_COOKIE["user"]; // Print a cookie

print_r($_COOKIE); // A way to view all cookies

?>


Deliting cookie
When deleting a cookie you should assure that the expiration date is in the
past.
Example
<?php
// set the expiration date to one hour ago
setcookie("user", "", time()-3600);
?>


Chapter 12

Sessions


Sessions
A PHP session variable is used to store information about, or change
settings for a user session.

Session variables hold information about one single user, and are
available to all pages in one application.


Starting a PHP Session
Before you can store user information in your PHP session, you must first
start up the session.
Session_start() is used to start a session
Example
<?php session_start(); ?>
<html>
<body>
</body>
</html>


Storing a Session Variable
Example
<?php
session_start();
$_SESSION['user']=”Ram”;
echo $_SESSION['user'];
?>
output:Ram


Destroying a Session
Unset() and session_destroy() are used to delete the session
unset():It is used to free the specified session variable:
Example of unset()
<?php
unset($_SESSION['views']);
?>

session_destroy():is used to compltetly destroy the session
Example of session_destroy()
<?php
session_destroy();
?>

Chapter 13

File Handling


File open
Fopen() is used to open a file
first parameter shows file name and the second parameter shows mode of
the file
Example
<?php
$file=fopen("welcome.txt","r");
?>


Closing a File
The fclose() function is used to close an open file:
Example
<?php
$file = fopen("test.txt","r");
//some code to be executed
fclose($file);
?>


Check End-of-file
The feof() function checks if the "end-of-file" (EOF) has been reached.
Example
<?php
if (feof($file))
echo "End of file";
?>


File Reading - Line by Line
The fgets() function is used to read a single line from a file.
Example
<?php
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file))
{
echo fgets($file). "<br />";
}
fclose($file);
?> www.opengurukul.com 101

File Reading - Character by
Character
The fgetc() function is used to read a single character from a file.
Example
<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
while (!feof($file))
{
echo fgetc($file);
}
fclose($file);
?>

File upload
Create an Upload-File Form
<html>
<body>
<form action="upload_file.php" method="post" enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file" />
<input type="submit" name="submit" value="Submit" />
</form>
</body>
</html>

Create The Upload Script
Example else

<?php {

if ($_FILES["file"]["error"] > 0) echo "Upload: " . $_FILES["file"]["name"]
. "<br />";
{
echo "Type: " . $_FILES["file"]["type"] .
echo "Error: " . $_FILES["file"]["error"] . "<br />";
"<br />";
echo "Size: " . ($_FILES["file"]["size"] /
} 1024) . " Kb<br />";
echo "Stored in: " . $_FILES["file"]
["tmp_name"];
}
?>

Restrictions on Upload
Example echo "Upload: " . $_FILES["file"]["name"] .
"<br />";
<?php
echo "Type: " . $_FILES["file"]["type"] . "<br
if ((($_FILES["file"]["type"] == "image/gif") || />";
($_FILES["file"]["type"] == "image/jpeg") ||
($_FILES["file"]["type"] == "image/pjpeg")) echo "Size: " . ($_FILES["file"]["size"] /
&& ($_FILES["file"]["size"] < 20000)) 1024) . " Kb<br />";

{ echo "Stored in: " . $_FILES["file"]
["tmp_name"];
if ($_FILES["file"]["error"] > 0)
}
{
}else
echo "Error: " . $_FILES["file"]["error"] . "<br
/>"; {

}else echo "Invalid file";

{ }
?>

Chapter 14

Sending Email


Sending Email using mail()
The PHP mail() function is used to Example
send emails from inside a script.
<?php
Syntax $to = "someone@example.com";
mail(to,subject,message,headers,pa $subject = "Test mail";
rameters)
$message = "Hello! This is a simple email
message.";
$from = "someonelse@example.com";

$headers = "From: $from";
mail($to,$subject,$message,$headers);

echo "Mail Sent."; ?>


Chapter 15

Error Handling


Default & Other Methods
The default error handling in PHP is very simple. An error message with
filename, line number and a message describing the error is sent to the
browser.
different error handling methods:
-Simple "die()" statements
-Custom errors and error triggers
-reporting


Basic Error Handling: Using the
die() function
Example
<?php if(!file_exists("welcome.txt"))
{

die("File not found");
}

Else
{

$file=fopen("welcome.txt","r");
}
?>

Now if the file does not exist you get an error like this: File not found

Creating a Custom Error Handler
This function must be able to handle a minimum of two parameters
i.e (error level and error message) but can accept up to five parameters
(optionally: file, line-number, and the error context):
Syntax
error_function(error_level,error_message,
error_file,error_line,error_context)


Error Report levels
E_WARNING: Non-fatal run-time errors
E_NOTICE: Run-time notices
E_USER_ERROR: Fatal user-generated error
E_USER_WARNING: Non-fatal user-generated warning
E_USER_NOTICE: User-generated notice
E_RECOVERABLE_ERROR: Catchable fatal error
E_ALL: All errors and warnings, except level E_STRICT


Set Error Handler
Syntax
set_error_handler("customError");
Example
<?php function customError($errno, $errstr) //error handler function

{
echo "<b>Error:</b> [$errno] $errstr";

}
set_error_handler("customError"); //set error handler

echo($test); //trigger error
?>

output: [8] Undefined variable: test

Trigger an Error
In a script where users can input data it is useful to trigger errors when an
illegal input occurs.trigger_error() function is used for this.
Example
<?php
$test=2;

if ($test>1)
{

trigger_error("Value must be 1 or below");
}
?>

output: Notice: Value must be 1 or below
in C:webfoldertest.php on line 6

Chapter 16

Exception Handling


Exception Handling
Exceptions are used to change the normal flow of a script if a specified error
occurs
We will show different error handling methods:
-Basic use of Exceptions
-Creating a custom exception handler
-Multiple exceptions
-Re-throwing an exception
-Setting a top level exception handler


Basic Use of Exceptions
When an exception is thrown, the code following it will not be executed, and
PHP will try to find the matching "catch" block.

If an exception is not caught, a fatal error will be issued with an "Uncaught
Exception" message.


Basic use of exception
output:Fatal error: Uncaught exception
Example 'Exception'
<?php with message 'Value must be 1 or
below' in C:webfoldertest.php:6
function checkNum($number)
Stack trace: #0
{ C:webfoldertest.php(12):
if($number>1) checkNum(28) #1 {main} thrown in C:
webfoldertest.php on line 6
{

throw new Exception("Value must be 1 or
below");
}

return true;
}
checkNum(2); ?>

Try, throw and catch
Try - A function using an exception should be in a "try" block.
If the exception does not trigger, the code will continue as normal. However
if the exception triggers, an exception is "thrown"

Throw - This is how you trigger an exception. Each "throw" must have at
least one "catch"

Catch - This block retrieves an exception and creates an object containing
the exception information


Try throw catch
Example Try

<?php {

function checkNum($number) checkNum(2);

{ echo 'If you see this, the number is 1 or
below';
if($number>1)
}
{
catch(Exception $e)
throw new Exception("Value must be 1 or
below"); {

} echo 'Message: ' .$e->getMessage();

return true; }

} ?>

www.opengurukul.com Message: Value must be 1 or below
output: 120

Chapter 17

Filter


Filters
PHP filters are used to validate and filter data coming from insecure
sources, like user input.

To test, validate and filter user input or custom data is an important part of
any web application.


Use of filter
We should always filter all external data!
What is external data?
-Input data from a form
-Cookies
-Web services data
-Server variables
-Database query results


Functions and Filters
To filter a variable, use one of the following filter functions:
filter_var() - Filters a single variable with a specified filter
filter_var_array() - Filter several variables with the same or different filters
filter_input - Get one input variable and filter it
filter_input_array - Get several input variables and filter them with the
same or different filters


filter_var()
Example of filters:we validate an integer using the filter_var() function:
$int = 123;
if(!filter_var($int, FILTER_VALIDATE_INT))
{
echo("Integer is not valid");
}
else
{
echo("Integer is valid");
}

Validating and Sanitizing
Are used to validate user input Are used to allow or disallow
specified characters in a string

Strict format rules (like URL or E-
Mail validating) No data format rules

Returns the expected type on
success or FALSE on failure
Always return the string


Validate input
Example else

<?php {

if(!filter_has_var(INPUT_GET, "email")) echo "E-Mail is valid";

{ }

echo("Input type does not exist"); }

} ?>

else The example tells

{ 1. Check if an "email" input variable of the
"GET" type exist
if (!filter_input(INPUT_GET, "email",
FILTER_VALIDATE_EMAIL)) 2. If the input variable exists, check if it is a
valid e-mail address
{

echo "E-Mail is not valid"; www.opengurukul.com 127

}

Sanitize Input
Example The example tells

<?php 1. Check if the "url" input of the "POST" type
exists
if(!filter_has_var(INPUT_POST, "url"))
2. If the input variable exists, sanitize (take
{ away invalid characters) and store it in the
$url variable
echo("Input type does not exist");

}
else

{
$url = filter_input(INPUT_POST, "url",
FILTER_SANITIZE_URL);
}


Chapter 18

PHP & MySQL


Connecting to a Database
In PHP,mysql_connect() function is used to connect the database
Syntax
mysql_connect( servername, username ,password);
Example
<?php
$con = mysql_connect("localhost","root","root”);
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
?>

Closing a Connection
The connection will be closed automatically when the script ends.
To close the connection before, use the mysql_close() function:
Example
<?php
$con = mysql_connect("localhost","root","root”);
if (!$con)
{
}
mysql_close($con);
?>

Creating Database
The CREATE DATABASE statement is used to create a database in
MySQL.
Syntax
CREATE DATABASE database_name
To execute the statement query we must use the mysql_query() function


Creating database
Example if (mysql_query("CREATE DATABASE
my_db",$con))
<?php
{
$con =
mysql_connect("localhost","root","root echo "Database created";
”);
}
if (!$con)
else
{
{
echo "Error creating database: " .
} mysql_error();
}
mysql_close($con);
?>

Creating Table
The CREATE TABLE statement is used to create a table in MySQL.
Syntax
CREATE TABLE table_name
(
column_name1 data_type,

)


Creating table
Example else

<?php {

$con = echo "Error creating database: " .
mysql_connect("localhost","root","root”); mysql_error();

if (!$con) }

{ mysql_select_db("my_db", $con);

die('Could not connect: ' . mysql_error()); $sql = "CREATE TABLE Persons

} (

if (mysql_query("CREATE DATABASE FirstName varchar(15),
my_db",$con))
LastName varchar(15),
{
)";
echo "Database created";
mysql_query($sql,$con);
}
mysql_close($con); ?>

Inserting data to DB
The INSERT INTO statement is used to add new records to a database
table.
Syntax
INSERT INTO table_name
VALUES (value1, value2, value3,...)

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...)


Insert Data From a Form Into a
Database
Here is the HTML form:form.php
<html>
<body>
<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname" />
Lastname: <input type="text" name="lastname" />
</form>
</body>
</html>

continue
In insert.php $sql="INSERT INTO Persons (FirstName,
LastName, Age)
<?php
VALUES
$con =
mysql_connect("localhost","root","root”); ('$_POST[firstname]','$_POST[lastname]','$_
POST[age]')";
if (!$con)
if (!mysql_query($sql,$con))
{
{
die('Error: ' . mysql_error());
}
}
mysql_select_db("my_db", $con);
echo "1 record added";
mysql_close($con)

?>

Select statement
It is used to select data from a mysql_select_db("my_db", $con);
database. $result = mysql_query("SELECT * FROM
Persons");
Syntax
while($row = mysql_fetch_array($result))
SELECT column_name(s) FROM
table_name {

echo $row['FirstName'] . " " .
Example $row['LastName'];
<?php echo "<br />";
$con = }
mysql_connect("localhost","root","root”);
mysql_close($con);
if (!$con)
?>
{
}

Update statement
It is used to update existing records if (!$con)
in a table. {

Syntax die('Could not connect: ' . mysql_error());

UPDATE table_name SET }
column1=value, mysql_select_db("my_db", $con);
column2=value2,...
mysql_query("UPDATE Persons SET Age =
WHERE some_column=some_value '36'
WHERE FirstName = 'Peter' AND LastName
Example = 'Griffin'");
<?php mysql_close($con);
$con = ?>


Delete statement
The DELETE FROM statement is if (!$con)
used to delete records from a {
database table.
Syntax
}
DELETE FROM table_name mysql_select_db("my_db", $con);
WHERE some_column =
some_value mysql_query("DELETE FROM Persons
WHERE LastName='Griffin'");
Example mysql_close($con);
<?php ?>
$con =


Important functions
mysql_num_rows:Get number of rows in result

mysql_affected_rows:Get number of affected rows in previous
MySQL operation

mysql_select_db:Select a MySQL database


mysql_num_rows
Example
<?php
$link = mysql_connect("localhost", "mysql_user", "mysql_password");
mysql_select_db("database", $link);
$result = mysql_query("SELECT * FROM table1", $link);
$num_rows = mysql_num_rows($result);
echo "$num_rows Rowsn";
?>


mysql_affected_rows
Example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');

if (!$link) {

}
mysql_select_db('mydb');

mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Records deleted: %dn", mysql_affected_rows());
mysql_query('DELETE FROM mytable WHERE 0');

printf("Records deleted: %dn", mysql_affected_rows());
?>

mysql_select_db
Example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Not connected : ' . mysql_error());
}
$db_selected = mysql_select_db('foo', $link);
if (!$db_selected) {
die ('Can't use foo : ' . mysql_error());
}

Chapter 19

PHP & ODBC


Create an ODBC Connection
Here is how to create an ODBC connection to a MS Access Database:
1.Open the Administrative Tools icon in your Control Panel.
2.Double-click on the Data Sources (ODBC) icon inside.
3. Choose the System DSN tab.
4.Click on Add in the System DSN tab.
5. Select the Microsoft Access Driver. Click Finish.
6. In the next screen, click Select to locate the database.
7.Give the database a Data Source Name (DSN).
8. Click OK.


DSN On Linux:
To use MySQL via ODBC:
<?php
$db_host = "server.mynetwork";
$db_user = "dbuser";
$db_pass = "dbpass";
$dsn = "DRIVER={MySQL ODBC 3.51 Driver};" .
"CommLinks=tcpip(Host=$db_host);" .
"DatabaseName=$db_name;" .
"uid=$db_user; pwd=$db_pass";
odbc_connect($dsn, $db_user, $db_pass);
?>

Connecting to an ODBC
The odbc_connect() is used to connect to an ODBC data source.
It takes four parameters:
-data source name
-username
-password
-optional cursor type.
Example
The following example creates a connection to a DSN called northwind, with
no username and no password.
$conn=odbc_connect('northwind','','');

Executing SQL Statement:
odbc_exec()
The odbc_exec() function is used to execute an SQL statement.
Example
example with no username and no password.
It then creates an SQL and executes it:
$conn=odbc_connect('northwind','','');
$sql="SELECT * FROM customers";
$rs=odbc_exec($conn,$sql);


Retrieving Records
odbc_fetch_row()
This function is used to return records from the result-set.
The function takes two parameters:
- ODBC result identifier
- an optional row number
Example
odbc_fetch_row($rs)


Retrieving Fields from a Record:
odbc_result()
This function is used to read fields from a record.
It takes two parameters:
-The ODBC result identifier
- a field number or name.
Example1
$compname=odbc_result($rs,1);
returns the value of the first field from the record:
Example2
$compname=odbc_result($rs,"CompanyName");
returns the value of a field called "CompanyName":

Closing an ODBC Connection:
odbc_close()
The odbc_close() function is used to close an ODBC connection.
Example
odbc_close($conn);


Chapter 20

Object Oriented
Programming


classes
A class is user defined data type that contains attributes or data
members; and methods which work on the data members.
Class structure
class <class-name>
{
<class body :- Data Members & Methods>;
}


Class example
class Customer //customer is the class name

{

private $first_name, $last_name; //$first_name/$last_name are attributes or data members.

public function setData($first_name, $last_name) //setData is the method

{

$this->first_name = $first_name;

$this->last_name = $last_name;

}

public function printData() //printData is also the method

{

echo $this->first_name . " : " . $this->last_name;

} www.opengurukul.com 156

}

The new instance
To create an instance of a class, the new keyword must be used.
An object will always be created when unless the object has a constructor defined
that throws an exception on error.
Classes should be defined before instantiation
If a string containing the name of a class is used with new, a new instance of that
class will be created.

Syntax
$instance = new Class();
Or we can write
$className = 'Foo';
$instance = new $className();

Object assignment
Example
$instance = new SimpleClass();
$assigned = $instance;
$reference =& $instance;
$instance->var = '$assigned will have this value';
$instance = null; // $instance and $reference become null
var_dump($instance);
var_dump($reference);
var_dump($assigned);


Extends keyword
A class can inherit the methods and }
properties of another class by $extended = new ExtendClass();
using the keyword extends in the
class declaration. $extended->displayVar();
?>
Example
output:Extending class
<?php
a default value
class ExtendClass extends SimpleClass

{
function displayVar()

{
echo "Extending classn";

parent::displayVar();
}

Properties
Class member variables are called "properties"
They are defined public, protected, or private, followed by a normal
variable declaration.
This declaration may include an initialization, but this initialization must be a
constant value


Properties
Example // valid property declarations:

<?php public $var6 = myConstant;

class SimpleClass public $var7 = array(true, false);

{ // This is allowed only in PHP 5.3.0 and later.

// invalid property declarations: public $var8 = <<<'EOD'

public $var1 = 'hello ' . 'world'; hello world

public $var2 = <<<EOD EOD;

hello world }

EOD; ?>

public $var3 = 1+2;

public $var4 = self::myStaticMethod();

public $var5 = $myVar; www.opengurukul.com 161

Class constants
Example
<?php
class MyClass

{
const constant = 'Any Testing Constant Value';

function showConstant() {
echo self::constant . "n";

}
}
echo MyClass::constant . "n";

?>
output: Any Testing Constant Value

Constructor
Syntax class SubClass extends BaseClass

void __construct ([ mixed $args [, $... ]] ) {

function __construct()
Example
{
<?php
parent::__construct();
class BaseClass
print "SubClass constructorn";
{
}
}
{
$obj = new BaseClass();
print "BaseClass constructorn";
$obj = new SubClass();
}
?>
}
www.opengurukul.com
Output: BaseClass constructor BaseClass 163
constructor SubClass constructor.

Destructor
Syntax function __destruct()
{
void __destruct ( void )
print "Destroying " . $this->name . "n";
Example
}
<?php
}
class MyDestructableClass
$obj = new MyDestructableClass();
{
?>
Output
{
In constructor Destroying
print "In constructorn"; MyDestructableClass
$this->name = "MyDestructableClass";

}

Object inheritance
Example class bar extends foo

<?php {

class foo public function printItem($string)

{ {

public function printItem($string) echo 'Bar: ' . $string . PHP_EOL;

{ }

echo 'Foo: ' . $string . PHP_EOL; }

} $foo = new foo(); $bar = new bar();

public function printPHP() $foo->printItem('baz'); // Output: 'Foo: baz'

{ $foo->printPHP(); // Output: 'PHP is great'

echo 'PHP is great.' . PHP_EOL; $bar->printItem('baz'); // Output: 'Bar: baz'

} $bar->printPHP(); // Output: 'PHP is great' ?>
} output:Foo: baz PHP is great. Bar: baz PHP is
great.

Scope Resolution Operator (::)
It is a token that allows access to static, constant, and overridden properties or
methods of a class.
The variable's value can not be a keyword (e.g. self, parent and static).

Example
<?php
class MyClass

{
const CONST_VALUE = 'Any constant value';

}
$classname = 'MyClass';

echo MyClass::CONST_VALUE; ?>
output:Any constant value www.opengurukul.com 166

Self and parent
Two special keywords self and parent class OtherClass extends MyClass
are used to access properties or {
methods from inside the class
definition. public static $my_static = 'static var';

public static function doubleColon()
Example
{
<?php
echo parent::CONST_VALUE . "<br>";
class MyClass
echo self::$my_static . "<br>";
{
}
const CONST_VALUE = 'Any constant value';
}
}
$classname = 'OtherClass';
$classname = 'MyClass';
OtherClass::doubleColon();

?>
Output: A constant value static var

Static keyword
Declaring class properties or methods as static makes them accessible without
needing an instantiation of the class.
A property declared as static can not be accessed with an instantiated class object .
The variable's value can not be a keyword (e.g. self, parent and static).


Static keyword
Example }

<? public function getStaticData()

class ClassName {

{ echo ClassName::$staticvariable; //Accessing Static
Variable
static private $staticvariable; //Defining Static
Variable }

function __construct($value) }

{ $a = new ClassName("12");

if($value != "") $a = new ClassName("23");

{ $a = new ClassName("");

ClassName::$staticvariable = $value; //Accessing ?>
Static Variable
Output:12
}
www.opengurukul.com 23 169
$this->getStaticData();
23

Abstract classes
It is not allowed to create an instance of a class that has been defined as abstract.
Syntax
<?

abstract class classname

{

//attributes and methods

abstract function methodname

}

class derived extends classname

{

function methodname


?>

Abstract class
Example class EmployeeData extends employee
//extending abstract class
<?
{
abstract class employee
function __construct($name,$age)
{
{
protected $empname;
$this->setdata($name,$age);
protected $empage;
}
function setdata($empname,$empage)
function outputData()
{
{
$this->empname = $empname;
echo $this->empname;
$this->empage = $empage;
echo $this->empage;
}
}
abstract function outputData();
www.opengurukul.com EmployeeData("Hitesh","24");
$a = new 171
}
$a->outputData(); ?> Output: Hitesh 24

Object interfaces
Interface is a object oriented concept,
It is the place where we can define the function.
Syntax
Interface interface_name
{

const 1;
const N;

function methodName1()
function methodNameN()

}


Object interfaces
Example function shimu()

<?php {

interface shahu print "<br />";

{ print self::lotu;

const lotu="lotu is lucky"; }

public function rooja(); }

} $hanu=new hasu();

class hasu implements shahu $hanu->rooja();

{ $hanu ->shimu();

public function rooja() ?>

print "<br />"; output:lotu is lucky

print self::lotu; print "<br />"; www.opengurukul.comhai roja 173

print "hai roja"; } lotu is lucky

Overloading
Overloading in PHP provides means to dynamically "create" properties and
methods.
All overloading methods must be defined as public.
Two types of overloading are there
-Property overloading
-Method overloading


Property overloading
Example
void __set ( string $name , mixed $value )

mixed __get ( string $name )
bool __isset ( string $name )

void __unset ( string $name )
The $name argument is the name of the property being interacted with.
__set() is run when writing data to inaccessible properties.

__get() is utilized for reading data from inaccessible properties.
__isset() is triggered by calling isset() or empty() on inaccessible properties.

__unset() is invoked when unset() is used on inaccessible properties.


Method overloading
Example
mixed __call ( string $name , array $arguments )
mixed __callStatic ( string $name , array $arguments )
-$name argument is the name of the method being called.
-The $arguments argument is an enumerated array containing the parameters
passed to the $name'ed method.
__call() is triggered when invoking inaccessible methods in an object context.

__callStatic() is triggered when invoking inaccessible methods in a static context.


Object iteration
PHP 5 provides a way for objects to be foreach($this as $key => $value)
defined so it is possible to iterate through
{
a list of items.
print "$key => $value<br>";
Example
}
<?php
}
class MyClass
}
{
$class = new MyClass();
public $var1 = 'value 1';
foreach($class as $key => $value)
{
print "$key => $value<br>";
protected $protected = 'protected var';
}
function iterateVisible()
echo "<br>";
{ www.opengurukul.com 177
$class->iterateVisible(); ?>
echo "MyClass::iterateVisible:n";

Magic methods
There are so many functions which are _wakeup
magical in php
_toString
_construct
_invoke
_destruct
_set_state
_call
_clone
_callStatic
_get
_set
_isset
_unset
_sleep

__sleep and __wakeup
Serialize()
checks if your class has a function with the magic name __sleep,
If so, that function is executed prior to any serialization

Unserialize()
checks for the presence of a function with the magic name __wakeup
If present, this function can reconstruct any resources that the object may have.


__toString,__invoke,__set_state
__toString
The __toString method allows a class to decide how it will react when it is treated like
a string.
__invoke
The __invoke method is called when a script tries to call an object as a function.
__set_state
This static method is called for classes exported by var_export() since PHP 5.1.0.


Final keyword
It prevents child classes from overriding a method by prefixing the definition with final.

If the class itself is being defined final then it cannot be extended.

Properties cannot be declared final, only classes and methods may be declared as
final.


Final keyword
Example
<?php

final class BaseClass {

public function test() {

echo "BaseClass::test() calledn";

}

final public function moreTesting() // Here it doesn't matter if you specify the function as final or not

{

echo "BaseClass::moreTesting() calledn";

}

}

class ChildClass extends BaseClass {
}// Results in Fatal error: Class ChildClass may not inherit from final class (BaseClass) ?>

Cloning object
it simply creates a copy of an object. $so = new SmallObject;
Example $so->field++;
$x = 1; $soRef = $so;
$y =& $x; $soClone = clone $so;
$x++; $so->field++;
echo"$y $x<br>"; echo $so->field; // outputs: 2
class SmallObject echo $soRef->field; // outputs: 2
{ echo $soClone->field; // outputs: 1
public $field = 0;
}

Late static binding
It can be used to refer the called class.

The name late static binding is coined because of the static:: will no longer be
resolved using the class where the method is defined.


Late static binding
Example class Two extends One {

public static function classIdentifier() {
<?php
echo __CLASS__;
class One {
}
public static function classIdentifier() {
}
echo __CLASS__;
Two::classtest();
}
?>
public static function classtest() {
Output: One
self::classIdentifier();

}

}


Objects and references
Example $d->foo = 2; // ($c,$d) = <id>

<?php echo $c->foo."n";

class A { $e = new A;

public $foo = 1; function foo($obj) {

} // ($obj) = ($e) = <id>

$a = new A; $obj->foo = 2;

$b = $a; // $a and $b are copies of the same }
identifier
foo($e);
// ($a) = ($b) = <id>
echo $e->foo."n";
$b->foo = 2;
?>
echo $a->foo."n";
output:2
$c = new A;
2
$d = &$c; // $c and $d are references www.opengurukul.com 186
2

Object serialization
Serialization in the context of storage and transmitting is the process of converting
an object into a sequence of bits
so that it can persist in a storage medium and or transmitted across a network.
serializing and unserializing can be done by two functions They are:
-Serialize
-unserialize
serialize() returns a string containing a byte-stream representation of any value
unserialize() can use this string to recreate the original variable values.


Chapter 21

PHP Built-in Functions


PHP Calendar Functions and
constants
cal_days_in_month:It Return the number of days in a month for a given year and
calendar.
Syntax:int cal_days_in_month ( int $calendar , int $month , int $year )
Parameters:calendar - Calendar to use for calculation
month - Month in the selected calendar
year - Year in the selected calendar
Example
<?php

$num = cal_days_in_month(CAL_GREGORIAN, 8, 2003);

echo "There was $num days in August 2003";

?>
www.opengurukul.com
Output -There was 31 days in August 2003 189

cal_info
It Returns information about a particular calendar.
Syntax:array cal_info ([ int $calendar = -1 ] )
Parameters:Calendar - Calendar to return information for. If no calendar is specified
information about all calendars is returned.
Example:<?php
$info = cal_info(0);

print_r($info);

?>

output:

Array ( [months] => Array ( [1] => January [2] => February [3] => March [4] => April [5] => May [6] =>
June [7] => July [8] => August [9] => September [10] => October [11] => November [


Many other calender function
cal_from_jd:It Converts from Julian Day Count to a supported calendar.
cal_to_jd:It Converts from a supported calendar to Julian Day Count.
FrenchToJD :It Converts a date from the French Republican Calendar to a
Julian Day Count.
GregorianToJD:It Converts a Gregorian date to Julian Day Count.


Date/time Functions and constants
Date function
The PHP date() function is used to format a time and/or date.
Syntax
date(format,timestamp) ;
Parameter
format - Required. Specifies the format of the timestamp
timestamp - Optional. Specifies a timestamp. Default is the current date and time.


Directory Functions and constants
Chdir: It change the directory
Syntax: bool chdir ( string $directory )
Parameters: directory - The new current directory
Example:<?php
// current directory

echo getcwd() . "n";
chdir('public_html');

?>

output:/home/vincent
/home/vincent/public_html

chroot
It change the root directory
Syntax
bool chroot ( string $directory )
Parameters
directory - The path to change the root directory to.
Example
<?php

chroot("/path/to/your/chroot/");

echo getcwd();

?>

output: /

getcwd
It gets the current working directory
Syntax: string getcwd ( void )
Example:<?php

chdir('cvs');

?>

output:/home/matsya
home/matsya/cvs

Error Logging functions and
constants
debug_backtrace: It generates a a_test('friend');
backtrace. include_once 'a.txt';

Syntax: array debug_backtrace ([ bool ?>
$provide_object = true ] )
a.txt:friend is the best part of my life
Parameters output:Hi: friendarray(1) { [0]=> array(4) { ["file"]=>
string(13) "/var/test.php" ["line"]=> int(10)
provide_object - Whether or not to ["function"]=> string(6) "a_test" ["args"]=>
populate the "object" index. array(1) { [0]=> &string(6) "friend" } } } friend is
the best part of my life
Example: <?php
function a_test($str)

{

echo "nHi: $str";

var_dump(debug_backtrace());


error_log
It send an error message somewhere
Syntax: bool error_log ( string $message [, int $message_type = 0 [, string $destination [,
string $extra_headers ]]] )

Parameters
message - The error message that should be logged.
message_type - Says where the error should go.
Destination - The destination. Its meaning depends on the message_type parameter as
described above.

extra_headers - The extra headers. It's used when the message_type parameter is set to 1.
Example:<?php

error_log("You messed up!", 3, "/var/tmp/my-errors.log");
?>

File System Functions and
constants
Basename
It returns trailing name component of path

Syntax
string basename ( string $path [, string $suffix ] )

Parameters
path - A path.

Suffix - If the name component ends in suffix this will also be cut off.

Example
<?php

echo "1) ".basename("/etc/sudoers.d", ".d").PHP_EOL;

echo "2) ".basename("/etc/passwd").PHP_EOL;


Output 1) sudoers 2) passwd

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