Top 10 PHP Interview Questions and Answers

Question 1: How to redirect a page to another?

Answer: You can use header function to redirect.
header('location: http://www.web-technology-experts-notes.in"); //Redirect to home page of another website

header('location: http://www.web-technology-experts-notes.in/2015/11/php-questions-and-answers-for-experienced.html"); //Redirect to another page and another website

header('location: php-questions-and-answers-for-experienced.html"); //Redirect to another page of same website

header('location: php-questions-and-answers-for-experienced.html?topic=php");  //Redirect to another page of same website with parameter

header('Location: http://www.web-technology-experts-notes.in/2015/11/php-questions-and-answers-for-experienced.html', true, 301); //Permanent Redirect

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Question 2: Is it secure to store a password in a session?

Answer: If you still need then please stored in encrypted form with different name (not password).

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Question 3: How to set/get PHP array in cookie?

Answer: //Set an array in cookie
$arrayData=json_encode(array(1,2,3,4,5,6));
setcookie('no_array', $arrayData);

//Get an array from cookie
$cookie = $_COOKIE['no_array'];
$arrayData = json_decode($cookie);
print_r($arrayData);

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Question 4: What is the difference between bindParam and bindValue?

Answer: $string='this is ';
if (strlen($string) != strlen(utf8_decode($string)))
{
    echo 'is unicode';
}else{
  echo 'It is Not unicode.';
}

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Question 5: How to add 30 mins to a date?

Answer: $date = date("Y-m-d H:i:s");
date("Y/m/d h:i:s", strtotime("+30 minutes", $date));

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Question 6: How to get Path From URL?

Answer: $url = "http://www.web-technology-experts-notes.in/2013/09/amazon-s3-introduction.html";
$path = parse_url($url);
print_r($path);
/**Array
(
    [scheme] => http
    [host] => www.web-technology-experts-notes.in
    [path] => /2013/09/amazon-s3-introduction.html
)*/

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Question 7: How to get array elements which present in two different array? 

Answer: $array1 = array("a" => "green", "red", "blue");
$array2 = array("b" => "green", "yellow", "red");
$result = array_intersect($array1, $array2);
print_r($result);
/**Array ( [a] => green [0] => red )*/

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Question 8: How to replace array elements with another another? 
Answer: $input = array("red", "green", "blue", "yellow");
array_splice($input, -1, 1, array("black", "maroon"));
print_r($input);

/*Array ( [0] => red [1] => green [2] => blue [3] => black [4] => maroon )*/

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Question 9: Count number of elements in an array? 

Answer: $foodArray = array('fruits' => array('orange', 'banana', 'apple'),
              'veggie' => array('carrot', 'collard', 'pea'));

echo count($foodArray); // output 2
// recursive count
echo count($foodArray, COUNT_RECURSIVE); // output 8

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Question 10: How to exchanges all keys with their associated values in an array? 

Answer: $input = array("oranges", "apples","mango", "pears");
$flippedArray = array_flip($input);

print_r($flippedArray);
/*Array ( [oranges] => 0 [apples] => 1 [mango] => 2 [pears] => 3 )*/