10 Common PHP Interview Questions asked by interviewers

10 Common PHP Interview Questions asked by interviewers
September 02, 2021

PHP stands for Hypertext Preprocessor. It is a scripting language designed to work with the HTTP protocol and provide interaction between the user and the server. It can be embedded in HTML or JavaScript, allowing both web developers and users to easily share data on the web. PHP is open-source software available for Windows, Mac OS X, Linux, Unix, BSD, Solaris, and other operating systems.

The interviewer will often start with a hypothetical problem that you can solve with PHP programming, or they might attempt to trap you by asking an irrelevant question about how to code something seemingly simple. Here we are going to see the most common PHP Interview Questions that are asked by most of the interviewers to select a candidate for a job.

1. What is Session?

Answer: Sessions are a unique combination of data that have been collected from the user input in a web browser and contains a link between the client-side and server-side applications. Sessions provide a way for user data to persist across many requests because that data is being saved at the session cookie. When users visit the page again, the user will be recognized as this user and you will know what information to return to them without asking for their login details.

2. What is Cookie?

Answer: A cookie is a plain-text string that is transferred from a user’s browser to a website. Detailed information about the users browsing activity can then be retrieved by the website and they may use that data to show advertisers. Cookies are also commonly used for authentication and help sites remember visitors when they log in on the website.

3. Give a List of top PHP Array Functions that are most used while development


  1. array_key_exists()
  2. array_keys()
  3. array_values()
  4. array_map()
  5. array_push()
  6. array_pop()
  7. array_reverse()
  8. array_search()
  9. array_splice()
  10. count()

4. Explain PHP Array Sort Methods


  1. sort() - Used to sort an indexed array in ascending order
  2. ksort() - Used to sort an associative array in ascending order, according to key
  3. krsort() - Used to sort an associative array in descending order, according to key
  4. asort() - Used to sort an associative array in ascending order, according to value
  5. arsort() - Used to sort an associative array in descending order, according to value

5. Give a List of top PHP Array Functions that are most used while development


  1. echo()
  2. print()
  3. strlen()
  4. strtolower()
  5. strtouper()
  6. strcmp()
  7. str_split()
  8. str_replace()

6. What is the difference between echo and print?


There are two major difference between echo and print that are:

  1. echo does not return anything while print returns the value 1 which can be used in expressions.
  2. echo can take multiple parameters while print can take one argument.

Echo is faster than print because it does not return value like print.

7.What is static variable?


A static variable is a variable that lives in the class rather than in an object of the class. This means that only one copy of the variable exists, and all objects created from this class will have access to it.

8. What is static function?


A static function is a function that can be invoked without creating an object of the class. Static functions are declared using the keyword "static" and need to be accessed outside the class through the use of :: operator.

9. What is Request Parameter? How to get request parameter value in PHP


The request parameter is the variable that is sent with each HTTP request. The PHP script will have all of the request parameters, which are stored in an associative array.

Following is the syntax to access the request parameter

//to access get request parameter
$nameParamValue = $_GET["name"];

//to access post request parameter
$nameParamValue = $_POST["name"];

10.What is the difference between implode and explode function in PHP?


implode is a function that Joins array elements with a string

$array = array('PHP''JavaScript''Python');
$comma_separated_value = implode(",", $array);

echo $comma_separated_value; // PHP,JavaScript,Python

explode is a function that returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string "separator".

// Exampl
$languages  = "PHP, JavaScript, Python";
$languages = explode(" ", $languages);
echo $languages[0]; // PHP
echo $languages[1]; // JavaScript

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