Top 50 PHP Interview Questions and Answers

Here we will complete some of the most frequently asked and most often answered Core PHP interview questions and answers. PHP jobs are being demanded every day more and more. Many who search or prepare for PHP jobs have to deal with specific common questions in the interview.
PHP Interview Questions and Answers

List of Core PHP interview questions most often asked, including detailed answers and code examples for fresh and skilled candidates.

Here we will complete some of the most frequently asked and most often answered Core PHP interview questions and answers for freshers and advanced PHP interview questions.


PHP jobs are being demanded every day more and more. Many who search or prepare for PHP jobs have to deal with specific common questions in the interview.

Therefore, if you are new and want to become a PHP developer or even a professional with a more professional job, you must read this article to improve your chances of achieving an easy and quick PHP job.


PHP Technical Interview Questions and Answers[Updated 2024]

PHP is a popular open-source web scripting language that enables developers to create dynamic and interactive websites. PHP is used by millions of web professionals all over the world, making it a powerful tool for creating robust, high-traffic websites.

PHP has been around for more than 10 years and continues to grow in popularity thanks to its flexibility and scalability. In terms of features, PHP offers an impressive array of abilities that can be put to use in a variety of web projects. This includes the ability to handle large volumes of traffic and manage complex database structures, as well as the capability to create custom scripts and modules that can be used in your own projects.

If you’re interested in learning more about PHP or want to develop a website using this powerful language, then be sure to check out our online and offline course offerings! We offer comprehensive training programs that will teach you everything you need to know about PHP development, including how to work with different web hosting platforms and databases. Our courses are designed for beginners as well as experienced developers who want to learn new techniques or improve their existing skillset. Learn at PHP Classes in Pune.

Let’s start with PHP Technical Interview Questions and Answers.


What is PHP?
PHP (Hypertext Preprocessor) is a server-side scripting language designed for web development. Hypertext Preprocessor is the complete version of PHP. It is used to create interactive content, communicate with a server, manages sessions, etc., by embedding HTML. It is one of the most popular scripting languages used for web development, and it powers millions of websites and web applications around the world. PHP is used for creating dynamic web pages, which can interact with a database and provide interactive elements to end users. PHP allows developers to create powerful and dynamic websites, as it can be used to create and process forms, generate dynamic web content, and interact with databases. It is an open-source language, so it can be edited and modified in order to create the desired functionality. PHP is very versatile and can be used to create simple or complex websites and applications. Additionally, PHP is easy to learn and use, making it a popular choice for web developers.


What is the difference between a client-side and a server-side language?

A client-side language is a type of programming language that is used to create and manage the content, structure, and design of a web page. It is typically executed by the web browser, meaning the code is interpreted and run on the user’s computer. Examples of client-side languages include HTML, CSS, JavaScript, AJAX, and jQuery.

A server-side language, on the other hand, is a type of programming language that is used to create web applications and web services that run on the web server. It is typically executed on the web server, meaning the code is processed before it is sent to the user’s computer. Examples of server-side languages include PHP, ASP.NET, Java, Python, and Ruby.

The primary difference between client-side and server-side languages is the location where the code is executed. Client-side code is executed on the user’s computer, while server-side code is executed on the web server. This means that server-side code is more secure since it is not accessible by the user’s computer. Additionally, client-side code is typically limited in terms of the types of tasks it can perform, while server-side code can be used for more complex tasks.


Why do we use PHP?

 The use of PHP has various advantages. It is entirely free to use. Anyone can use PHP at minimum costs to host the site.

It supports a variety of databases. MySQL, which is now free to use, is the most widely used database. Many PHP frameworks, such as CodeIgniter, CakePHP, Laravel, etc., are now used for web development.

What are the main features of PHP?

The main features of PHP are:

1. Easy to use and learn: PHP is a very simple and easy language to learn. It has a lot of built-in functions and libraries that make coding much easier.

2. Open source: PHP is open source and free to use. This makes it very accessible to anyone who wants to use it.

3. Cross-platform: PHP is compatible with many different operating systems, such as Windows, Linux, Unix, and Mac OS X.

4. Support for databases: PHP has native support for many different databases, such as MySQL, PostgreSQL, Oracle, and Microsoft SQL Server.

5. Security: PHP has many built-in security features to help protect your website from malicious attacks.

6. Performance: PHP is a very fast and efficient language, making it ideal for creating dynamic websites and applications


What is the difference between PHP and HTML?

PHP and HTML are two different languages that are used for different purposes. HTML (HyperText Markup Language) is a markup language used to structure and present content on the web. It is used to create static web pages that are displayed in a web browser. It is composed of elements such as text, links, images, and other multimedia content.

On the other hand, PHP (Hypertext Preprocessor) is a scripting language that is used for building dynamic web pages. It is used to develop interactive web applications such as forums, blogs, and ecommerce websites. PHP is processed on the server-side, meaning that the code is executed on the web server and the resulting HTML is sent to the browser. PHP also enables a website to store and retrieve information from a database.

In summary, HTML is used to create static web pages, while PHP is used to create dynamic web applications. HTML is used for displaying web content, while PHP is used for manipulating web content.


What is the difference between PHP and JavaScript?

PHP and JavaScript are two popular scripting languages used to create dynamic webpages. Both languages are used extensively in web development, but they are quite different from each other.

PHP is a server-side scripting language which is processed on the server before the web page is loaded in the browser. It is mainly used for creating web pages that interact with a database. PHP can create page content, manage user sessions and pass data from one page to the next.

JavaScript is a client-side scripting language which is executed in the browser. JavaScript is mainly used to create dynamic web pages that can interact with the user. It can be used to validate forms, create drop down menus and display data in real time.

In summary, PHP is a server-side scripting language and JavaScript is a client-side scripting language. PHP is mainly used to create dynamic webpages that interact with a database, while JavaScript is mainly used to create interactive webpages that interact with the user.


Is PHP a strongly typed language?

PHP is a language that is weakly typed. It implies that PHP does not need to declare data types of the variable when declaring any variable like the other C+ or Java standard programming languages. When you store the value of a string in a variable, the type of data is a string, and the kind of data is an integer if you store a numerical value in the same variable.


How do you connect to a MySQL database from PHP?

1. Establish a connection to the MySQL database using the mysqli_connect() function. This takes 4 arguments – the server address, username, password, and the name of the database being accessed.

2. Create a query to send to the database. This is done by using the mysqli_query() function, which takes two arguments – the connection to the database and the query.

3. Execute the query by using the mysqli_query() function. This will return a result set which can be used to loop through and output the results.

4. Close the connection to the database using the mysqli_close() function. This will ensure that the connection is properly closed and any data is saved.


What is mean by variable variables in PHP?

If the variable value is used as the name of the other variables, it is considered a variable. The variables in PHP are declared by $$.|


What is the purpose of the ternary operator in PHP?

The ternary operator is used to assign a value to a variable based on a condition. It is a shorthand way of writing an if-else statement.

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What is the purpose of the global keyword in PHP?

The global keyword in PHP is used to access global variables from within functions or other scopes. It allows a user to access a global variable from within a function, or from within a class method.

When a global keyword is used, it tells PHP to look for the variable outside of the current scope. Without the global keyword, the variable would only be accessible within the function or class.

The global keyword can also be used to create new global variables, as long as the variable name is not already taken.

Using the global keyword can improve code readability, as it makes it easier to understand which variables are global and which are local. It can also reduce the amount of code that needs to be written, as it eliminates the need to pass variables around as parameters.


What is the difference between echo and print in PHP?

The primary difference between echo and print in PHP is that echo has no return value while print has a return value of 1 which can be used in expressions. The echo and print method both print the output from the browser, but the two practices vary. After printing output, echo doesn’t return any value and operates better than printing. The print method is slower than the echo, as it produces the boolean value.

Echo is a language construct used to output one or more strings. It is a faster way to output data to the browser as it does not involve the use of function and it can take multiple parameters (although such usage is rare).

Print is also a language construct used to output a string. It is a slower way to output data to the browser as it involves the use of a function. Unlike echo, it can only take one argument.

The echo statement can also be used with multiple strings and variables whereas the print statement cannot.

In terms of performance, echo is slightly faster than print.


What is the purpose of the switch statement in PHP?

The switch statement in PHP is a type of control flow statement that helps developers to execute a specific set of statements based on the value of an expression. It is similar to the if-else statement in that it allows a program to execute one or more statements based on a given value, but it is often used to execute a set of related statements instead of just two.

The switch statement is used to evaluate a single expression and then execute a set of related statements based on that expression. For example, if you wanted to check if a user has a certain type of account, you could use a switch statement to do so. The switch statement would check the value of the expression and then execute the appropriate set of statements depending on the result.

The expression is evaluated first. If the result matches one of the defined case values, then the statements associated with that case value are executed. If no match is found, the default statement is executed.

A switch statement can contain any number of case values and associated statements, and each case value can be of any type. However, the switch statement will only evaluate the expression once, so the cases must all use the same type.

Switch statements can be nested, meaning a switch statement can be used inside another switch statement. This can be useful to break down the logic of a program further and make it easier to read and understand.

It’s important to note that each case statement must end with the break keyword. If you don’t include the break keyword, then the program will execute all of the statements after the matched case and any default statements.

The switch statement is an efficient and elegant way of structuring and executing related statements based on a single expression. It can be used in place of the if-else statement for simpler programs, or it can be used to break down more complex logic into smaller, more manageable chunks.


What is the difference between an if statement and a switch statement in PHP?

An if statement is a type of control structure that allows a programmer to execute code if a certain condition evaluates to true. A switch statement is also a type of control structure, but is used when multiple conditions must be evaluated.

An if statement uses a comparison operator to determine if a statement is true or false. The comparison operator can be any of the seven comparison operators (‘==’, ‘!=’, ‘===’, ‘!==’, ”, ‘=’). An if statement can contain multiple conditions and use logical operators (‘&&’,’||’ and ‘!’) to combine them.

A switch statement is structured differently than an if statement. Instead of using comparison operators, a switch statement uses the value of a single expression to evaluate multiple conditions. Each condition is represented by a case statement and the switch statement will execute the code associated with the first case statement whose expression evaluates to true. A switch statement also requires a default case, which is executed when none of the other case statements evaluate to true.

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What is the difference between single and double quotes in PHP?

The primary difference between single and double quotes in PHP is how they interpret certain characters. Single quotes will treat most characters as literal values, while double quotes will interpret certain characters as special characters.

Single quotes will treat most characters within the quotes as literal values, including special characters like newlines and tabs. For example, ‘Hello\nWorld’ will be displayed as “Hello\nWorld” without any changes.

Double quotes will interpret certain characters within the quotes as special characters. For example, “Hello\nWorld” will be displayed as “Hello World”, with the newline character being interpreted. Double quotes will also interpret variables within the quotes as their values. For example, if $name is equal to “John”, then “Hello $name” will be displayed as “Hello John”.

In summary, single quotes will treat most characters within the quotes as literal values, while double quotes will interpret certain characters and variables as special characters or values.


What is the difference between the functions implode() and explode()?

The functions implode() and explode() are two PHP string functions that are often used to manipulate strings. Implode, also known as join, is used to convert an array of strings into a single string. It takes two parameters, an array of strings and a separator string. The output of implode is a single string with each array element separated by the separator.

Explode is the opposite of implode, and is used to convert a string into an array of strings. It takes two parameters, a string and a separator. The output of explode is an array of strings, with each element being a substring of the original string that is separated by the separator.

In summary, implode is used to convert an array of strings into a single string, while explode is used to convert a string into an array of strings. The main difference between the two functions is that implode takes an array of strings as input and outputs a single string, while explode takes a single string as input and outputs an array of strings. In addition, implode takes a separator string as a parameter while explode takes a separator as a parameter.

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What is the difference between a static and a dynamic website?

A static website is a website that displays the same content every time it is accessed. The content on a static website is coded in HTML and does not change, even when the user interacts with it. The content is stored on a web server and is the same for all users.

A dynamic website, on the other hand, is a website that changes and adapts depending on the user’s input. The content is stored in a database and is updated as the user interacts with the website. The content is generated in real-time from the database and is tailored to the user’s needs. Dynamic websites are more interactive than static websites and feature content that changes depending on the user’s actions. They are also more complex in terms of coding and require more development time.


What is an associative array in PHP?

An associative array in PHP is an array that uses named keys that you assign to each element in the array. This is in contrast to a regular array, which uses incremental numeric keys assigned automatically. Associative arrays are useful for storing sets of key/value pairs of data, such as user preferences or other data associated with a particular user.


To check the data type of variable, Which function is used in PHP?

The function gettype() is used to check any variable’s data type.


How you increase the maximum execution time of a script in PHP?

To increase the maximum execution time, change the value of the max execution time directive in the php.ini file. If you want to set the maximum execution time of 120 seconds, set maxexecutiontime = 120 seconds and the following value.


Using PHP, how do you connect to a MySQL server?

To communicate with the MySQL server in mysqli_connect() form, the MySQL hostname, user name, and password must be provided, or mysqli-class database object declared.


How do you use PHP to retrieve data from a MySQL database?

There are some PHP functions for retrieving data from the MySQL database. 

Difference between mysqli_connect and mysqli_pconnect?

● MySQL connect() function used to establish a long-lasting database connection that does not end when the script ends.

● The method mysqli connect() looks for any known persistence connection and, if there is no persistence connection, creates a new database connection and ends a connection at the end of the script.

● The PHP new version is depreciated by the mysqli connect() function, but you can create a connection for persistently using a prefix with mysqli connect.


Difference between substr() and strstr()?

The substr() function returns the start point and length part of a string. For this function, the Length Parameter is optional, and when it is omitted, the remaining portion of the string will return from the starting point.

strstr() searches for the first string to appear inside another string. 


How long does a PHP session last?

In PHP, session data is default to last 24 minutes or 1440 seconds. But you can change the duration by changing the GC maxlifetime directive value in a php.ini file. Open php.ini file and set the GC maxlifetime directive to set the session duration for 30 minutes, GC maxlifetime = 1800.


What is the difference between a session and a cookie in PHP?

A session and a cookie are two techniques used in web development to store and retrieve user data. They are both used to keep track of a user’s identity and activity on a website, but they differ in their implementation and usage.

A session is a temporary storage space on the server that is used to store information about a user’s activity on a website. A session is typically created when a user visits a website and is stored on the server until the user leaves the website. The session is identified by a session ID, which is a unique identifier for the session. This session ID is sent to the user’s browser and stored as a cookie, which is then used to identify the user when the user visits the website again.

A cookie, on the other hand, is a small piece of data stored on the user’s computer. It is typically used to store information about the user, such as their username and preferences, or to store session data. Cookies are also used to track user activity on a website, such as when a user has visited a particular page or clicked a certain link. Cookies can also be used to store user preferences, such as language or font size, so that they are automatically applied when the user visits the website again.

The main difference between a session and a cookie is that a session is stored on the server while a cookie is stored on the user’s computer. This means that a session is more secure than a cookie since it is stored on a separate machine and cannot be accessed by anyone other than the server. Additionally, a session is stored for a limited amount of time, and once the user leaves the website, the session is destroyed. Cookies, on the other hand, can remain stored on the user’s computer for a longer period of time and can be accessed by the website at any time.

In summary, a session and a cookie are two different tools used in web development to store and retrieve user data. A session is stored on the server and is used to store information about a user’s activity on a website, while a cookie is stored on the user’s computer and is used to store user preferences or track user activity. Sessions are more secure than cookies since they are stored on a separate machine, while cookies can remain stored on the user’s computer for a longer period of time.


How do you set a cookie in PHP?

Setting a cookie in PHP is a very simple process. First, you need to use the set cookie() function to set the cookie. This function takes a few parameters:

1. The name of the cookie (string).

2. The value of the cookie (string).

3. The expiration date of the cookie (integer, in seconds).

4. The path on the server in which the cookie will be available (string).

5. The domain that the cookie is available to (string).

6. Whether the cookie should only be sent over a secure connection (boolean).

Once the set cookie() function has been called, the cookie will be set and available to the user.

For example:

setcookie(‘username’, ‘John Doe’, time()+60*60*24*7, ‘/’, ‘example.com’, true);

This will create a cookie called ‘username’ with a value of ‘John Doe’, that is available for a week and only available over a secure connection


What is the difference between the functions unlink() and unset()?

The unlink () function is used to remove files from the file system, while the unset() function is used to remove variables from the current scope.

The unlink() function takes a single argument which is the path to the file to be deleted. This function will return true if the file is successfully removed, and false if an error is encountered.

The unset() function takes a single argument which is the name of the variable to be removed. This function will return true if the variable is successfully removed, or false if the variable does not exist.

In summary, unlink() is used to remove files from the file system, while unset() is used to remove variables from the current scope.


What is the difference between the functions count and sizeof()?

The difference between the functions count() and sizeof() is that count() is used to count the number of elements in an array, while sizeof() is used to calculate the size of an array in bytes.

The count() function is a built-in function in PHP that returns the number of elements in an array. It takes an array as an argument and returns the number of elements in the array.

The sizeof() function is a language construct that returns the size of an array in bytes. It takes an array as an argument and returns the size of the array in bytes. It is important to note that sizeof() does not return the number of elements in the array, but rather the size of the array in bytes.

In summary, count() is used to count the number of elements in an array, while sizeof() is used to calculate the size of an array in bytes.

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What is the difference between the functions strlen() and strcmp()?

The strlen() function is used to find the length of a given string. This function takes one argument, which is the input string, and returns the length of the string as an integer.

The strcmp()function takes two arguments, which are the two strings to be compared, and returns an integer value. If the two strings are the same, the function will return 0; if the first string is greater than the second string, the function will return a positive value; and if the first string is less than the second string, the function will return a negative value.


What is the difference between a while and a do-while loop?

A while loop is a type of loop that checks its condition before executing the code in the loop. This means that if the condition is false, the loop will never run. Until the condition is no longer true, the while loop will keep looping.

A do-while loop is a type of loop that checks its condition after executing the code in the loop. This means that the loop will always run at least once, even if the condition is false. The do-while loop will continue to loop until the condition is no longer true.


What is the purpose of the break and continue statements?

The break and continue statements are used to control the flow of a loop in a program. The break statement is used to terminate the loop in which it is present, while the continue statement is used to skip the current iteration and move on to the next one.

The break statement is most commonly used in the context of a loop. It is used to immediately exit the loop and move on to the code following the loop. This is useful when a certain condition is met, and the loop does not need to continue. For example, if a loop is searching through a list of numbers for a certain value, and it finds the value, a break statement can be used to stop the loop from continuing to search for the value.

The continue statement is also used in a loop. It is used to skip the remainder of the current iteration and move on to the next iteration. This is useful when certain conditions are met, and the program does not need to perform any further actions for the current iteration. For example, if a loop is searching through a list of numbers for a certain value, and it finds that the current number is larger than the value being searched for, a continue statement can be used to skip the remainder of that iteration and move on to the next one.

The break and continue statements are essential tools for controlling the flow of a loop in a program. They can be used to exit a loop when a certain condition is met, or to skip the remainder of the current iteration and move on to the next one. This allows the programmer to create more efficient and concise code, resulting in faster and more efficient program execution.


Use of the mysqli_real_escape_string() function?

The function mysqli@real escape string() is used to avoid specific string characters to use a SQL statement.


What functions are used to remove whitespaces from the string?

In PHP, there are three functions to remove string whitespace.

● trim() – Removes the left and right sides of a string of whitespaces.

● ltrim() – Removes the left side of the string of whitespaces.

● rtrim() – Removes the right side string from the whitespaces.


What is a persistence cookie?

The persistence cookie is a cookie file permanently stored on the browser. It is not secure and is used mainly for a long time to track a visitor.


What are Public, private, protected, static, and final scopes?

● Public – anywhere you can access variables, classes, and methods declared public.

● Private – The parent class can access only variables, classes and methods declared private.

● Protected – Parent and child classes have only access to variables, classes, and procedures that have been declared protected.

● Static – After losing the scope, the static variable will keep the value.

● Final – This scope prevents children from declaring the same item again.

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Explain difference between an abstract class and an interface?

For closely related objects, the abstract classes are used, and unrelated objects interfaces are used. PHP class can implement many interfaces, but it is unable to inherit multiple classes. 


What is URL rewriting?

The rewriting of the URL is called the URL of the session ID in every local URL of the requested page.

 The user can quickly copy, paste, and send the URL to another user.


What is PDO?

PHP Data Objects is the full form of PDO.

It’s a lightweight PHP extension that uses a consistent interface to access the database. The developer can quickly move from one database server to the other using PDO. However, this does not support all the new MySQL server’s advanced features.


What are the different PHP data types?

● String: a character sequence, e.g., “Hackr.io.”

● Float: a (decimal) number of floating points, e.g., 23.450

● Integer: an integer, for example, 12

● Boolean: it’s two states – true, false.

● Object: store in the single entity, like apple = New Fruit(), values of different data types;

● Series: stores several same type values, like array (“red”, “yellow”, “blue”)

● NULL: when the variable is not assigned a value, NULL will be assigned. for example, $msg = NULL.


Explain isset() function?

The isset() function verifies if the variable, in particular, is set with a value of NULL. Returns a Boolean function – false if the value is not set or if it is set, 

the function is able to check many values: isset(var1, var2, var3).


What is the purpose of the isset() and unset() functions?

The isset() and unset() functions are two of the most commonly used functions in PHP. The isset() function is used to check if a variable is set, meaning it has been assigned a value. This is useful when testing if a variable exists before attempting to use it. The unset() function is used to destroy a variable or an element of an array. This is useful when you want to free up memory or remove variables that are no longer needed. Both functions are commonly used in conditional statements to ensure that a variable is set before attempting to use it. By checking if a variable is set, you can avoid errors and unwanted behavior in your code.


What is the difference between the functions isset and empty?

The isset() and empty() functions are used to check if a variable is set or not.

The isset() function is used to check if a variable has a value assigned to it. It returns true if the variable is set and is not NULL.

The empty() function is used to check if a variable is empty or not. It will return true if the variable is empty or not set. It will return false if the variable is set and has a non-empty, non-zero value.

In summary, the isset() function is used to check if a variable is set and has a value, while the empty() function is used to check if a variable is empty or not set.

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What the difference is between include and require in PHP?

All are constructed and can be named by myfile.php inclusion without parentheses. However, if the file is not considered to be used, a warning will be sent, and the script will continue. Require will make a fatal mistake, and then and there, the script stops. If the file is essential to the script, then it can be used.

Include and require are both language constructs that are used to include a file within another file. The main difference between them is how they handle errors.

Include:

They include statement will produce a warning (E_WARNING) and the script will continue execution.


Require:

The require statement will produce a fatal error (E_COMPILE_ERROR) and halt the execution of the script.

In other words, if the file specified in the include statement cannot be found, the script will still run, but it may not do what you expect it to do. If the file specified in the require statement cannot be found, the script will not run at all.


What is the purpose of the include and require statements?

The include and require statements are used to include the code from a specified file into the current file. This is useful for separating code into multiple files and ensuring that code is executed in the correct order.

Include and require are similar in that they both read the code from the specified file and execute it. The main difference between the two is that if an error occurs when using include, the script will continue to execute, while if an error occurs when using require, the script will stop executing.

Include is generally used when a file contains functions or variables that may be used in multiple scripts and will not cause an error if it fails to be included. Require is generally used when the code contained in the specified file is essential for the script to execute correctly, and an error should be thrown if the file fails to be included.

In conclusion, the purpose of the include and require statements is to read and execute the code from a specified file in order to separate code into multiple files and make sure that the right order of code execution is followed.

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What is the significance of the Parser in PHP?

PHP parser is a software that converts the source code of the computer. The parser translates any series of instructions we send in the form of a code into an automatically readable format. Use the token to get all functions to parse PHP code using PHP.


Explain Path Traversal?

Path Traversal is a way to attack the web application’s files. ‘../’ is defined as the sequences for dot-dot. It’s a cross-platform symbol that can add to the directory. Path Traversal uses the dot-dot-slash sequences to handle the web app file.

You can reveal the file from a web server or application through the root directory of Path Traversal. It is usually done for access tokens, hidden passwords, and other sensitive file information.

Traversal Path is also known as Traversal Directory. It enables the attacker to exploit vulnerabilities in the targeted web file.


How can you pass data from one page to another in PHP?

Data can be transferred from one web page to another in PHP using a variety of techniques. The most common way to pass data from one page to another is to use the HTTP GET and POST methods. The GET method is used to pass data as part of the URL, while the POST method is used to pass data in an HTTP request body.

Using the GET method, data can be passed from one page to another by appending query strings to the URL.

When using the POST method, data is passed as part of an HTTP request body. This method is more secure than the GET method because the data is not visible in the URL. To use the POST method, you’ll need to add a form to your page with an input field for each piece of data that you want to pass. Each input field will need a name attribute that corresponds to the data that it’s sending. For example, if you wanted to pass a variable called “name”, you would need to add an input field with a name attribute of “name”.

Once you’ve created the form, you’ll need to set the action attribute of the form to the URL of the page that you’re sending the data to. You’ll also need to set the method attribute of the form to “POST”. When the form is submitted, the data will be passed to the specified page.

In addition to using the GET and POST methods, data can also be passed from one page to another using cookies. Cookies are small pieces of data stored in the user’s browser that can be used to store information. To use cookies, you’ll need to set the data that you want to pass in a cookie and then retrieve it on the other page.

Finally, data can also be passed from one page to another using sessions. Sessions are variables that are stored on the server and can be used to store data across multiple pages. To use sessions, you’ll need to start a session on the page that you’re sending the data from and set the data that you want to pass in a session variable. Then, on the other page, you can retrieve the session variable to access the data that was passed.

In conclusion, there are a number of different ways to pass data from one page to another in PHP. The most common methods are using the GET and POST methods, using cookies, and using sessions. Each method has its own advantages and disadvantages, so it’s important to choose the one that is best suited for your specific needs.


Describe the distinction between POST requests and GET

Any PHP developer must understand the HTTP protocol properly. The distinctions between GET and POST are essential when learning the HTTP protocol. Here are the key differences in the two requests:

● The GET method requires the data to be displayed as part of the URL. Since the data is embedded in the request, this is not the case for POST.

● GET manages a maximum number of characters of 2048. Such restrictions on POST are not imposed.

● GET supports only ASCII data. On the other hand, POST makes all ASCII, binary data, and other data forms.

● GET is generally used for data retrieval, while POST would use for data update and insertion.


What is the difference between a static and an instance method in PHP?

Static methods are methods that are declared with the static keyword and are accessible without creating an instance of the class. They can be called directly via the class name and do not require an object instance to be created. They are used to define methods that are not related to a specific object instance.

Instance methods are methods that are declared without the static keyword and can only be called by creating an instance of the class. They are used to define methods that are related to a specific object instance. Instance methods have access to the object’s data and can modify it. They also have access to static methods and static properties.


What is the difference between the functions print_r() and var_dump()?

The main difference between print_r() and var_dump() is the type of output they produce.

To print information about a variable that is readable by humans, use the print r() method. It is useful for debugging and for quickly seeing the contents of an array. The output of print_r() is a string that can be easily read by humans.

The var_dump() function is used to display structured information about variables including type and value. This function is also useful for debugging. The output of var_dump() is more detailed than print_r(). It includes the data type, value and length of the variable. It also displays the array keys and elements.


Describe the critical function as well as its syntax.

In PHP, the mail() function is used to transfer email directly from a script or a website. It has five arguments in all. A mail function general syntax is as follows:

● To denote the email recipient

● Subject indicates email subject

● The message is the actual message that will deliver by email.

● Headers display additional mail content, for example, CC and BCC.

● Parameters indicate some extra parameters to be entered in the mail sending program (Optional)


In PHP, what are Memcache and Memcached? Can a single Memcache instance be shared between several PHP projects?

Memcached is an efficient cache daemon specially built for load decrease in dynamic web applications. The Memcache module offers Memcached an easy, procedural, and object-oriented interface. Memcache is a storage space, and Memcache can be used on only one or more servers. Consequently, a single instance of Memcache can share various projects.

A client may configure to speak to several instances. Two different Memcache processes can also run on the same host. Although it works on the same host, all functions in Memcache remain independent unless there is a data partition.


When PHP changes, how do you keep Memcached up to date?

When PHP codes are changed, there are two methods of updating Memcached:

● Clear Cache Proactively – It is to clear the cache during insert or update.

● Cache Reset – Reset values after the update or insert is completed.


How is PHP object comparison done?

The operator ‘==’ would check to see if two objects will have the same class instance with the same attributes and values. To test the use of identity operator ‘===’ to test whether two objects belong to one example of the same class.


What are PHP destructors and constructors?

When a PHP-class object is created and destroyed, PHP constructors and destructors are a unique function type. The destructor frees the tools provided by or used by a class because a constructor initializes private class variables.


Explain common types of errors in PHP?

PHP supports three types of errors:

● Notices – Errors that are not critical. It occurs during the script execution. Underlined variable access is a Notice instance.

● Warnings – errors of greater priority than warnings. As in the case of Notices, the execution of a warning script is uninterrupted. A Notice example includes a non-existent file.

● Fatal Mistake – The execution of a script ends until such an error occurs—a non-existing object property results in a fatal error.


What are the main benefits of PHP 7 compared to PHP 5?

● Support for the integer of 64-bit – while PHP 7 supports native 64-bit integers and large files, PHP 5 does not endorse any of them.

● PHP 7 works well better than PHP 5 performance. PHP 7 uses PHP-NG ( Next Generation), while PHP 5 uses Zend II.

● Return Type – A significant downside to PHP 5 is that the return type may not define. 

● Error handling – Handling fatal errors in PHP 5 is complex. On the opposite, a new Exception Objects engine comes in PHP 7. It allows managing some crucial mistakes, now replaced by exceptions.

● Anonymous class – We have the class anonymous in PHP 7 to maximize its performance to run the class once. PHP 5 doesn’t have that.

● The Declaration of Group Use – PHP 7 allows all classes, constants, and functions to be grouped from the same namespace into a single-use declaration. It is called the declaration for group use. PHP 5 does not offer the feature.

● New Operators – PHP 7 is being introduced with several new operators, including ‘<=>’ and ‘??’. The former is considered the three-way comparator, and the latter is called the null coalescing operator.


What are the different ways to handle Mysql’s PHP result set?

The MySQL result set can be handled in four ways:

● mysqli_fetch_row

● mysqli_fetch_object

● mysqli_fetch_assoc

● mysqli_fetch_array


What are the Traits in PHP?

The mechanism allows reusable code to be created in PHP languages where several inheritances are not supported. A trait cannot individually instantiate.


What is a session in PHP? 

The easiest way to store data with a single session ID for individual users is with a PHP session. It is used to keep states on the server and to share data over many files. It is due to HTTP being a stateless protocol.

Session IDs are usually sent via session cookies to the browser. The ID is used to retrieve existing data from the session. PHP opens a new session if a session ID is not on the server, and then a unique ID is created.


Which is the best hashing method for passwords?

It is easier for users to use either crypt() or hash than typical hash algorithms, including md5, sha1, and sha256 (). Though crypt() supports many hashing algorithms natively, hash(,) provides even more support.


Do you know any workarounds? Why isn’t possible for JavaScript and PHP to interact directly? 

No direct interaction between JS and PHP is possible since although the first language is on the client-side, the latter language is on the server-side. The two leading programming languages can interact indirectly using exchange variables.

This variable exchange has two reasons: 

● JavaScript code for the browser can be executed by PHP 1.

● A particular variable may return to PHP via URL.

Since PHP is always executed before JavaScript, it is necessary to transfer the JS variables through a form or URL. GET, and POST is used for passing the variables. Similarly, $_GET and $_POST is used to retrieve the passed variable.


Describe PHP and a few popular PHP frameworks.

PHP is a common server scripting language for developing web pages dynamically. The original meaning of PHP is Personal Home Page. But for the recursive acronym PHP, today stands for it: the Hypertext Preprocessor.

There are several PHP frameworks available right now. The following briefly explains three popular PHP frameworks:

● CodeIgniter – CodeIgniter is a simple and efficient PHP framework with a hassle-free installation and minimalist configuration requirements. The whole system is just 2 MB, and the documentation is included. CodeIgniter is ideal in developing dynamic sites, as it comes with several prebuilt modules that help create strong, reusable components. The popular PHP application also provides an efficient working experience both on dedicated and shared hosting platforms.

● Laravel – Laravel may not be the oldest popular PHP framework, but not as old as any more famous PHP frameworks. Launched in 2010, PHP’s ability to provide additional speed and security for managing complicated web applications is a significant contributor to its popularity. Laravel also facilitates the development of repetitive tasks, including authentication, routing, sessions, and queuing, by reducing complexity.

● Symfony – PHP developers have used the famous PHP Framework since its release in 2005. Over its almost one and a half-decade, it has matured. Symfony is a comprehensive PHP platform and the only PHP framework that fully supports PHP and web. Various components of Symfony are used by popular CMSs, including Drupal, OroCRM, and PHPBB.


Explain difference between passing a variable by value and passing a variable by reference in PHP?

The variable’s value is directly passed to the named function as you pass the variable by value. The value stored in the variable would be used. The source variable is unchanged by changes made to the process.

The variable containing the value is passed to the called function when passing the variable by reference. It uses the value stored in the past address. Any changes to the function would affect the source variable.


What do typecasting and type juggling mean?

Typecasting is the process of directly converting the data type of a variable by the user. Variable declarations in PHP do not allow for explicit type definition. The context in which a variable is used determines its data type,As a result.

If you add a string value to a $var variable, it will automatically be converted to a string. Similarly, if you add an integer value to $var, it will become an integer. It is called type juggling.


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Conclusion

Keep cool during the interview and be confident. While it is essential to have a good knowledge of technical concepts, the presentation is also reviewed.

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