PHP Interview Questions 6-10

7. How can we extract string ‘techinterviews.com ‘ from a string ‘http://www.techinterviews.com’ using regular expression of PHP?

Type 1

'<'?php
preg_match('@^(?:http://)?([^/]+)@i',
"http://www.php.net/index.html",$matches);
$host=$matches[1];


preg_match('/[^.]+\.[^.]+$/', $host, $matches);
echo "domain name is: {$matches[0]}\n";
?>

type 2

'<'?php

preg_match ( "/^(http:\/\/www\.)?([^\/]+)/i" , "http://www.jacksiva.blogpot.com/siva/jack/index.html" , $matches );

echo $matches [ 2 ].'
'; //echo $host -> jacksiva.blogspot.com

?>

type 3

preg_match ( "/^(http:\/\/)?([^\/]+)/i" , "http://www.jacksiva.blogpot.com/siva/index.html" , $matches );

$host = $matches [ 2 ]; //echo $host -> www.jacksiva.blogspot.com

preg_match ( "/[^.]+\.[^.]+\.[^.]+$/i" , $host, $matches );

echo $host2 = $matches[0];

?>

output: php.net

note:

asterisk ("*") has the meaning "some or none" or "zero or more."

The plus-sign ("+") means "one or more times"

The question-mark ("?") means "zero or one times."

email validation:

'<'?php
if (isset($_POST['submit'])){
$emailfield=$_POST['emailfield'];
echo $emailfield;
$okay=preg_match('/^[A-z0-9_\-\.]+[@][A-z0-9_\-]+([.][A-z0-9_\-])+[A-z]{2,4}$/',$emailfield);
if($okay){
echo "E-mail is validated";
}else{
echo"E-mail is incorrect";
}
}
?>
'<'form method="POST" action="email.php">
E-mail address: '<'input type="text" name="emailfield">
'<'input type="submit" name="submit" value="Validate">



8.How can we create a database using PHP and mysql?
$con = mysql_connect("localhost","peter","abc123");
mysql_query("CREATE DATABASE my_db",$con);

9. What are the differences between require and include, include_once?

include();--> include the file, but in case of file missing

throws a warning and continues execution of code of next line.
require();; require also includes the file but in case of file missing throws an fatal error
and stop the execution of the code of next line.
include_once();if same file was included first it will not include the file another time.
but include( ) using more than one time.

10. Can we use include (”techinterviews.php”) two times in a PHP page “makeit.PHP”?

Yes. To use include () two time is possible.