Monday 12 January 2015

PHP Technical Interview Questions and Answers for Fresher and Experienced

PHP Technical Interview Questions and Answers for Fresher and Experienced



Question: How to convert string to array in php?
$string="cakephp and zend";
$array =explode('and',$string);
print_r($array);


Question: How to convert array to string in php?
$array = array('cakephp','zend');
$string =implode(' and ',$array);
echo $string;


Question: How to connect mysqli with php using Object-Oriented Way?
$host = "localhost";
$username = "root";
$password = "";
$conn = new mysqli($host, $username, $password);
//connect to server
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully";


Question: How to connect mysqli with php using Procedural Way?
$host = "localhost";
$username = "root";
$password = "";
$conn = mysqli_connect($host, $username, $password);
//connect to server
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully";


Question: How to connect mysqli with php using PDO?
$host = "localhost";
$username = "root";
$password = "";
 $conn = new PDO("mysql:host=$host;dbname=myDB", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";


Question: Give Curl example using post method?
$postData = array(
   "site" => "web technology experts notes",
   "dailyuser" => "1000",
   "location" => "India"
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://www.example.com");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
$output = curl_exec($ch);
curl_close($ch);
echo $output;




Question: How to destroy one session?
unset($_SESSION['object']);


Question: How to Destroys all data registered to a session?
session_destroy();


Question: How to delete a php file from server?
$file="full_path/filename.php"
unlink($file); //make sure you have enough permission to do delete the file.


Question: How to convert string to uppercase in php?
$string="cakephp and zend";
echo strtoupper($string);


Question: How to convert string to lowercase in php?
$string="CAKEPHP AND ZEND";
echo strtolower($string);


Question: How to convert first letter of string to uppercase in php?
$string="cakephp and zend";
echo ucwords($string);


Question: Difference between array_merge and array_combine in php?
array_merge example
$array1 = array('one','two');
$array2 = array(1,2);
$result = array_merge($array1,$array2);
print_r($result);

array_combine example
$array1 = array('one','two');
$array2 = array(1,2);
$result = array_combine($array1,$array2);
print_r($result);


Question: How to convert array to json in php?
$array = array('one','two');
echo json_encode($array); //use json_decode for decode 


Question: How to serialize an array in php?
$array = array('one','two');
echo serialize($array);//use unserialize for convert serialized string to array


Question: How to get ip address in php?
$_SERVER['REMOTE_ADDR']


Question: How to count the number of elements in an array?
$array = array('cakephp','zend');
sizeof($array);
count($array);


Question: How to call constructor of parent class?
parent::constructor()


Question: What is use of var_dump?
It is used to display the data-type and values of variable. For Example.
$name='WTEN';
var_dump($name);



Question: What is final class
It is class which can not be inherited.
Following are example of final class
final class baseclass{
        public function testmethod()  {
            echo  "base class method";
        }
}


Question: How can we define constants in PHP?
define('WTEN','Web Technology Experts Notes'); //How to define constants
echo WTEN;//How to use constants




Question: How to start displaying errors in PHP application ? Add following code in PHP.
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

OR
Add following code in .htacess
php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag  log_errors on