PHP

PHP Interview Questions 2022

Today we are going to discuss Top PHP Interview Questions 2022.

Table of Contents

1) What is PHP?

PHP is a server-side programming language it is used for building dynamic web applications.

2) What is PEAR stands for?

Pear in PHP is the abbreviation of Php Extension and Application Repository.

3) Who developed PHP?

Rasmus Lerdorf developed PHP in 1994.

4) Tell the full abbreviation of PHP?

Before the full abbreviation of PHP was Personal home page but now it stands for Hypertext Processor.

5) Why do we use PHP?

Because PHP is a simple and easy-to-handle programming language and by using PHP we can develop large complex projects like eCommerce websites, crud systems, etc. 

6) Tell the Difference between echo and print?

There is a very slight difference between both terms, echo does not contain a return value while print contains a return value which is 1. Overall both echo and print work the same.

7) How does javascript interact with PHP?

As we know that javascript is a client-side scripting language and PHP is a server-side programming language so they cant interact directly while the variables are exchangeable so PHP can compile javascript code through the browser. 

8) Why do we use foreach loop in PHP?

The foreach loop is used for arrays when we want to print the elements of the array in PHP.

9) What is hashing password method in PHP?

Hashing a password is a function in PHP that stores multiple passwords in a single password and it creates a new password.

10) Tell the difference between include() and require() methods?

Both terms are used to add a file in your current code file the only difference is while including a file using include() and you received an error so the further execution of the file will be stopped if we talk about require() so it doesn’t happen with it. The execution doesn’t stop even if an error occurred.

11) How to create a database connection in PHP?

For creating a connection with the database you have to make a database first, then in your code file write the following code:

mysqli_connect(“localhost”, ”root”, ” ”, “database name”);

Note: The password will be blank.

12) Tell the difference between get and post methods?

The difference between get and post is if you use GET so the information related to the user will be shown in the URL while the POST method is more secure than get Method, it doesn’t show the information in the URL.

13) How to execute PHP script from the command line?

To execute the PHP script we will run a PHP command in the command line like below:

 PHP index.php

14) Tell the difference between “= =” and “= = =” operators?

Both operators are used to check the equality. the difference is the ===operator is strictly equivalent and checks the data types as well. 

15) What type of errors can be occurred in PHP?

Four types of errors can occur in PHP.

1)fatal errors

2)notice errors

3)warning errors

4)parse errors

16) Does PHP support multiple inheritances?

No PHP does not support multiple inheritances. it supports only single inheritance.

17) What are the differences between session and cookie?

Sessions and cookies both terms store information when a user visits a website, the only difference is that cookies are stored in the client-side machine where sessions are stored on both sides, the client-side and server-side.

18) What is PDO?

PDO in PHP stands for (Php Data Objects) it is an abstract data access layer that allows a developer to access the database and fetch the data through functions and queries easily.

19) What are traits?

Traits in PHP are a kind of mechanism which is used to provide certain reusable perks of multiple inheritances. It allows programmers that they can use a combination of functions again from distinct classes. Traits can be used in those languages where multiple inheritances is not supportable.

20) Tell the difference between Single-quoted and double-quoted string in PHP?

The difference between single and double-quoted strings is the single-quoted string does not print the value of the variable it treats it like a constant while the double-quoted string shows the value of the variable.

21) How to Concatenate 2 strings in PHP?

We can concatenate 2 strings by using the dot(.) between them in PHP.

22) Define the rules for naming a variable in PHP?

A variable in php can’t be start with any special character like ! @ # $ % ^ & *() +.

23) Is PHP a Case Sensitive Programming Language?

In PHP the overall function names are not case sensitive but variables and constants are.

24) What is a Constant defined in PHP?

Constant define is used to define the value of a constant. we can use it by declaring the defined function in the PHP script.

25) Tell the difference between Php4 and PHP5?

In Php 4 both the constructor and destructor have the same name while in php5 they are declared as _constructor and _destructor.

In php4 we can declare an abstract class while in php5 we cannot.

In php4 we can pass almost everything by passing its value

In php5 we can pass objects only by reference.

 

26) Tell the difference between Static and dynamic websites?

In static websites, we can’t change the content but in dynamic websites, we can change it at run time and the content will regenerate whenever a user reloads the site.

Static means a solution that is not permanent or we can say which is done deceptively but workable.

dynamic is a complete backend work and dynamic solutions are permanent and the right way of doing a task where you want to interact with the database.

27) Tell the name of Popular CMS of Php?

  • WordPress
  • Joomla
  • Magneto
  • Drupal

28) What is a Constructor and Destructor in PHP?

Constructor and destructor are two methods in PHP. A constructor is used to create new objects by passing parameters easily while destructors are used to vanish or delete the objects.

29) What is the purpose of Php ini file?

The purpose of the PHP .ini file is to make changes in the PHP program according to your wish. It is a configuration file you can access in your PHP setup folder.

There are a lot of things like variables, resource limits, and file timeouts that you can control.

30) What is escaping to PHP?

Escaping to PHP means informing the PHP parser function that a few PHP code elements are distinct from PHP script so treat them accordingly.

31) What are the two most common ways to start and finish a PHP block of code?

<?php [ php code]  ?> // 1st way
<? [Php code] ?> // 2nd way

32 What is the final class and a final method?

The final keyword is added before class the declaration of the final method will not allow being overridden by other classes.

33) Does Php interact with HTML?

Yes, PHP interacts with HTML. HTML is the whole structure of the web page so we can add PHP script to the HTML page for making it dynamic.

34) Tell the names of Popular frameworks of PHP?

There are 6 popular frameworks of PHP.

  • CakePHP
  • Laravel
  • Zend
  • Phalcon
  • Yii 2
  • Codeigniter

35) Tell the difference between require and require once?

The only difference between both terms is, required is used when we did not include a file. It adds the file even if the file is already included, while require once checks the existence of the file first if it is included so it does not include it again.

36) Define different types of Array in PHP?

There are 3 types of arrays in PHP

1)Index arrays (a single array like [“php”,”JS”,”html”])

2)Associative array (an arrays with key elements like [a=>”php”,b=>”js”,c=>”html”])

3)Multidimensional array(multiple arrays in a single array like (arrays [“php”,”JS”,”html”],[a=>”php”,b=>”js”,c=>”html”])

37) How to set an infinite execution time for PHP script?

We can set an infinite execution time for the PHP script by using the set_time_limit(0) function at the start of the PHP script.

38) What is the difference between asp net and PHP?

An ASP.NET is a framework for windows used for building desktop applications while PHP is a server-side programming language that is used for building websites.  

39) What is the difference between $message and $$message in Php?

The only difference between $message and $$message is that $message is just a normal variable whose name can’t be changed while $$message is a reference variable that store the data about $message.

40) What are PHP Magic Methods/Functions?

The magic methods in PHP are those essential methods that perform a specific task and are called automatically when it applies to a certain object. It starts with a double underscore (__).

Some of the magic methods are:

  • __construct()
  • __destruct()
  • __set()
  • __get()
  • __call()
  • __toString()
  • __sleep()
  • __isset()

41) What is Type hinting in PHP?

Type hinting in PHP is a technique to provide hints to functions so they can accept only those data types which we declare in a program.

42) How to connect to a URL in PHP?

Well, there is a library in PHP (cURL) that stands for client URL, it is used to connect a URL in PHP all you have to do is just add that library to your PHP file.

43) What is null?

The null is a data type that has no value. We assign null to a variable when we want to assign nothing.

we can assign null in both uppercase and lowercase.

44) Different types of variables in PHP?

There are 9 data types in PHP:

  1. integer
  2. Boolean
  3. double
  4. null
  5. strings
  6. objects
  7. resources
  8. arrays
  9. float

45) What is the purpose of break and continue statements?

The break statement stops the execution where we want to check if the condition is satisfied or not while the continue statement is used to check if the condition is satisfied or true so it will continue executing.

46) How to compare objects in PHP?

We can use the == operator for comparing two objects in PHP. We can check if both objects are inherited from the same class and contains the same attributes or not.

47) What is the use of constant function in PHP?

A constant function is used when you have no idea about the variable name.

48) How can a text be printed using PHP?

A text can be printed in two ways using PHP.

<?php echo “text here”; ?>
//or
<?php Print “text here” ;?>

49) How are the comments used in PHP?

A single line comment can be commented by adding “#” at the start of the comment line and you can comment on multiple lines by adding/* at the start and */ at the end of the comment line.

50) What is the most used method for hashing passwords in PHP?

The crypt() method is used for hashing passwords in PHP. It includes some algorithms which make this functionality easier and possible. These algorithms are md5, sha1, and sha256.

51) How can we get the IP address of a client in PHP?

We can get the IP address of a connected client only by using the following variable. $_SERVER[“REMOTE_ ADDR”];

52) What is the use of lambda functions in PHP?

It is a function in PHP that stores the data in a variable and pass it as an argument so we can use it later or whenever we need that variable.

 function($x) {return $x>2;});

53) Differentiate between compile-time exception and runtime exception in PHP?

When a kind of exception occurs during the compilation of a script then it is called compile time exception. i.e file not found.

When a kind of error occurred and it stops the execution of the script then it is called a runtime exception. i.e ArrayIndexOutofBound.

54) How we can get the number of elements in an array?

Using PHP’s count function, we can easily get the number of elements in an array.

55) What is the use of the $REQUEST variable?

The $REQUEST variable is used when a form of data is submitted to the server. The $request variable reads the data from the HTML form and prints the submitted values.

56). Which functions are used to remove whitespaces from the string?

Three functions can be used to remove whitespaces from the string.

1) trim (it removes the whitespaces from both left and right sides of the string).  

2) ltrim (it removes the whitespaces from the left side of the string).

3) rtrim (it removes the whitespaces from the right side of the string).

57) What is Memcache?

A Memcache in PHP is a mechanism that is used to increase the speed and enhance the performance of a website. Memcache is used by many famous websites like Facebook, Google, etc.  

58) What are the functions to be used to get the image’s properties (size, width, and height)?

The getimagesize(), imagesx(), and imagesy() functions can be used to get the size width, and height of the image.

59) What is the function file_get_contents() useful for?

This function is very useful because it allows the developer to read a file and store the file in a string variable as well.

60) Which function gives us the number of affected entries by a query?

The mysqli_affected_rows function is used to get the number of affected entries by a query in PHP.

Conclusion

In this article, we covered all those important questions which can be asked you in your PHP interview so make sure to prepare yourself for all those questions.

Hope this tutorial will be helpful for you and hope you like it as well if you have any queries regarding this article so feel free to contact us below. Thanks for reading. 

 

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