Exclusive list of Interview Questions asked when you hire dedicated php developers in India
What is PHP?
The acronym PHP represents "Hypertext Preprocessor." The main use for this server-side scripting language is web development. PHP scripts run on the server to produce dynamic webpages or to retrieve and edit data in databases before sending the finished product to the client's web browser.
Explain the difference between single quotes ('') and double quotes ("") in PHP.
PHP string literals are defined using single quotes ('') and double quotes (""). Variables and escape sequences are not parsed when using single quotes since everything inside them is treated as a literal string. On the other hand, escape sequence interpretation and variable interpolation are made possible by double quotes.
What is the purpose of a PHP session?
One technique to keep track of a user's information over several pages or website visits is with a PHP session. Data like user preferences, authentication status, and contents of the shopping cart can all be persistently stored thanks to it. Sessions function by giving each user a distinct ID, which is transferred by cookies or URL parameters between the client's browser and the server. During a user's visit to the website, session data is accessible and modifiable on the server.
How do you start a PHP session?
Use the session_start() function at the start of your PHP script to initiate a PHP session. This function starts a brand-new session or, if one already exists, picks it back up. Prior to any output being provided to the browser, it needs to be called.
Explain the concept of PHP superglobal variables.
Predefined variables called PHP superglobal variables are accessible in all scopes of a PHP script. They give users access to a variety of data, including cookies, form inputs, server information, session data, and more. Superglobal variables, such as $_GET, $_POST, $_SESSION, $_COOKIE, $_SERVER, and $_FILES, are preceded with a $_ (underscore followed by an uppercase letter). There is no need to designate these variables as global because they may be accessed from anywhere in the script.
How do you connect to a MySQL database using PHP?
For connecting to MySQL databases, PHP provides a number of extensions, such as PDO (PHP Data Objects) and MySQLi (MySQL Improved).
What are the advantages of using PHP?
PHP has many benefits, such as being simple to learn and use, working with a wide range of web servers and operating systems, having a huge community of supporters, and having a lot of pre-built modules and frameworks accessible.
What are variables in PHP, and how are they declared?
Data values are stored in PHP variables. The variable name is used after the $ symbol in their declaration. As an illustration: $name is "John";
What is the PHP variable's scope?
Where a variable can be accessed in PHP is determined by its scope. Three variable scopes are supported by PHP: local, global, and static.
How do you include one PHP file in another PHP file?
The require() and include() functions allow you to incorporate one PHP file inside another.
What are PHP superglobal variables? Name some of them.
Predefined variables called PHP superglobal variables can be accessed from anywhere in the PHP script. Superglobal variables in PHP that are frequently used are $_GET, $_POST, $_SESSION, $_COOKIE, $_SERVER, and $_FILES.
What is the difference between == and === operators in PHP?
The == (equal) operator in PHP determines whether two values are equal regardless of the data types of the values. The === (identical) operator, on the other hand, determines whether two values are equivalent and belong to the same data type.
1. Difference between include vs. require and require_once vs. include_once?
The main distinction between require and include is that while both include and require evaluate a given file, require will result in a fatal error if the file cannot be located, whereas include will just issue a warning.
How do you handle errors and exceptions in PHP?
Try-catch blocks in PHP can be used to manage exceptions and errors. The code that could raise an exception is included in the try block, and any exceptions raised inside the try block are handled by the catch block. Furthermore, code can be executed using the finally block even if an exception was not thrown.
What is the purpose of the foreach loop in PHP?
To iterate over arrays and objects in PHP, utilize the foreach loop. It lets you to loop through every property in an object or every element in an array, running a block of code each time.
In PHP, what is method chaining and how is it accomplished?
In object-oriented programming, method chaining is a technique that involves calling many methods on the same object sequentially. Because repeated variable assignments are avoided, the code can be written in a cleaner, more concise manner. In order to accomplish method chaining, each method must return the actual object ($this) after completing its task.
Explain the function of PHP's static keyword.
To declare class members (properties and methods) that are part of the class itself rather than instances of the class, use the static keyword in PHP. No need to instantiate the class is required to access static properties and methods. They are accessible via the scope resolution operator (::) and shared by all instances of the class.
Describe the function of the PHP trait keyword.
To define reusable sets of methods that may be used in multiple classes, one uses the trait keyword in PHP. Although they cannot be instantiated on their own, traits are comparable to classes. By enabling developers to reuse methods across several classes without utilizing inheritance, they are meant to decrease code duplication and enhance code organization. Classes incorporate traits by use the use keyword.
How is inheritance implemented in PHP?
The ability for a class (subclass or child class) to inherit methods and properties from another class (superclass or parent class) is known as inheritance in PHP. The parent class name and the extends keyword are used to implement inheritance. All public and protected methods and properties from the parent class are passed down to the subclass.
What is the purpose of interfaces in PHP?
In PHP, an interface specifies a contract that classes are allowed to implement. They provide a list of methods that classes that implement them have to define. In order to accomplish abstraction and guarantee that classes follow a particular behavior without controlling how that behavior is implemented, interfaces are utilized. They make code reuse easier and permit polymorphism.
Explain the purpose of abstract classes in PHP
In PHP, abstract classes are those that have the potential to contain abstract methods and are incapable of being created on their own. Concrete subclasses are where abstract methods must be implemented; they are defined but not implemented in the abstract class. Without offering a full implementation, abstract classes are used to enforce specific behavior and establish a standard interface for subclasses. In inheritance hierarchies, where several classes exhibit common behavior, they are frequently employed.
In PHP, how are file uploads handled?
In PHP, the $_FILES superglobal array is used to manage file uploads. PHP fills the $_FILES array with details about a file submitted through a form with the enctype="multipart/form-data" tag. These details include the file's name, type, size, and temporary placement on the server.
Describe the function json_encode() in PHP and its purpose.
How can JSON data be parsed in PHP?
PHP's json_decode() function can be used to parse JSON data. This function accepts a string in JSON as input and outputs a PHP variable (array or object) for handling in the future.
Explain the function called file_get_contents() in PHP.
To read a file's contents into a string in PHP, use the file_get_contents() method. It accepts a filename or URL as input and outputs, in string form, the contents of the file. This function is frequently used to read and manipulate data in PHP files, including JSON, text, and XML files.
In PHP, how do you read from and write to a file?
PHP provides a number of functions for reading from and writing to files, including file_get_contents(), file_put_contents(), fopen(), fwrite(), and fread().
Describe the distinctions between the PHP methods file() and fopen().
In PHP, files can be opened and read using both the file() and fopen() functions, but they act in distinct ways: The function fopen() opens a file or URL and provides a resource that points to the file for use in reading, writing, or appending to the file, among other activities. The function file() reads a whole file into an array. After the newline character is eliminated, each element of the array represents a line from the file.
What does PHP's fclose() function accomplish?
In PHP, an open file pointer supplied by the fopen() function can be closed using the fclose() function. In order to guarantee that any data buffered in memory is written to the file and to free up system resources, it is crucial to close a file pointer. Closing files after you've finished reading or writing to them is a recommended practice.
Explain the purpose of the unlink() function in PHP
The unlink() function in PHP is utilized for the purpose of removing a file from the filesystem. It tries to remove the file indicated by the path after receiving the filename as input. Unlink() returns true if it is successful and false otherwise. Using unlink() should be done with caution since it removes files from the filesystem permanently.
In PHP, how can one read the contents of a directory?
The scandir() function in PHP or the glob() function with a wildcard pattern can both be used to read the contents of a directory. An array of filenames and directories in the given directory, including the current directory (.) and the parent directory (..), is returned by the scandir() function.
In PHP, how do you make and remove directories?
The mkdir() and rmdir() functions in PHP allow you to create and delete directories, respectively. A new directory with the given pathname and optional permissions is created using the mkdir() function. If the supplied directory is empty, the rmdir() method removes it.
How do you rename a file or directory in PHP?
The rename() function in PHP allows you to rename files or directories. The old filename or directory name and the new filename or directory name are the two parameters required by this function. Rename() returns true if the operation is successful and false otherwise.
In PHP, how can one determine whether a file or directory is readable or writable?
The is_readable() and is_writable() functions in PHP allow you to determine whether a file or directory is writable or readable, respectively. Both functions accept a filename or directory name as input and, depending on which one is used, return true if the input is readable or writeable. They return false otherwise.
Describe the function of PHP's header() function.
To deliver raw HTTP headers to the client's web browser, utilize PHP's header() function. Before a webpage's actual content, headers are used to send additional data, such as HTTP status codes, content types, cookies, and caching directives. Before any output, not even blank lines or whitespace, is transmitted to the browser, the header() method needs to be invoked.
Explain the function of PHP cookies.
In PHP, cookies are discrete bits of information that are kept on the client's web browser. Between HTTP requests and responses, they are used to persistently store data, including session identifiers, user preferences, and the contents of shopping carts. Both the client and the server can access and modify cookies since they are transmitted between them as HTTP headers. The setcookie() method in PHP can be used to set cookies, and the $_COOKIE superglobal array can be used to retrieve them.
In PHP, how do you end a session?
The session_destroy() function in PHP allows you to terminate a session and reset all of its variables. This function clears the session data from the server and ends the active session. It's frequently used when a user closes their browser window or when their session ends.
Describe the objective of PHP Cross-Site Scripting (XSS) attacks.
The answer is that when malicious scripts are inserted into web pages that are read by other users, it can lead to Cross-Site Scripting (XSS) attacks in PHP. Sensitive data, including session cookies, login passwords, and personal information, can be stolen from unwary users using cross-site scripting (XSS) attacks. XSS attacks can be classified into three primary categories: reflected XSS, stored XSS, and DOM-based XSS. In order to prevent user-supplied data from being executed as code in the browser, effective input validation and output escaping are necessary to prevent XSS attacks.
What is SQL injection, and what steps can PHP take to prevent it?
In response, SQL injection is a kind of security flaw that arises when a hacker manages to insert malicious SQL code via user input into a database query. This may result in data modification, unauthorized database access, and even total program control. Using parameterized queries (prepared statements) or escaping user input before combining it into SQL queries are two ways to stop SQL injection attacks in PHP. User input is handled as data rather than executable code when a query is parameterized, which prevents the query's structure from changing.
Explain the purpose of the htmlspecialchars() function in PHP.
Describe Cross-Site Request Forgery (CSRF) and explain how to stop it with PHP.
In response, a hacker may employ a technique known as Cross-Site Request Forgery (CSRF) to deceive a user into inadvertently carrying out an operation on a web application without authorization. Usually, this is accomplished by taking advantage of the user's authenticated session to carry out tasks, such altering account settings or executing unsanctioned transactions. PHP CSRF attacks can be avoided by putting in place safeguards like CSRF tokens, referer header or origin validation for requests, and reauthentication requirements for sensitive activities.
Describe the function of the PHP filter_var() function.
To filter and validate data against a defined filter or validation rule, utilize PHP's filter_var() function. It is frequently used to validate and sanitize user-supplied data to make sure it satisfies requirements like being a valid email address, URL, or integer. The input data to be filtered and the filter to be applied are the two parameters that filter_var() requires. If the validation is successful, it returns the filtered data; otherwise, it returns false if the data does not satisfy the requirements.
In PHP, how are exceptions handled?
Try-catch blocks are used in PHP to manage exceptions. The code that could raise an exception is included in the try block, and any exceptions raised inside the try block are handled by the catch block. You can also use a finally block to run code whether or not an exception was raised, or numerous catch blocks to handle different kinds of exceptions.
Describe the distinction between PHP's unset() and unset($_SESSION).
The unset() method in PHP can be used to remove one or more variables from the system. It unsets all session variables when used with $_SESSION. Nevertheless, the session and its related session data are essentially destroyed when unset($_SESSION) is used since it directly targets the $_SESSION variable.
What does PHP's array_map() function accomplish?
To apply a callback function to each element of an array, use PHP's array_map() function. It requires two parameters: the array to be operated on and the callback function to apply. The results of applying the callback function to each element of the input array are returned by array_map() as an array. Value transformation and modification are frequent actions carried out on arrays using this function.
Describe the function of the PHP array_filter() function.
To filter elements of an array using a callback function, utilize PHP's array_filter() function. The array to filter and the callback function, which chooses which elements to include in the resultant array, are the two parameters it requires. When an element should be included, the callback function should return true; when an element should be excluded, it should return false. An array with only the elements for which the callback function returns true is returned by array_filter().
How do you handle file uploads in PHP with multiple files?
The answer is to use an HTML form with the multiple attribute on the file input field to handle file uploads with multiple files in PHP. Users can now choose several files to upload thanks to this. Using the $_FILES superglobal array, which has an array of file metadata for each uploaded file, you may access the uploaded files on the PHP side. Once these arrays are created, you may handle each file separately by iterating over them.
What does PHP's array_merge() function accomplish?
The array_merge() method in PHP is utilized for the purpose of combining several arrays into a single array. It accepts several arrays as inputs and outputs a new array with every element from the input arrays. The later value will overwrite the earlier one if the same string keys are present in two or more input arrays.
Describe the function of PHP's array_key_exists().
The array_key_exists() function in PHP is utilized to determine if a given key is present in an array. The array to search and the key to check are its two required arguments. array_key_exists() returns true if the key is present in the array and false otherwise. When attempting to access array elements, this function is frequently used to prevent undefined index issues.
What is the PHP function array_unique() used for?
The PHP method array_unique() is utilized to eliminate duplicate values from an array. The array from which duplicate values are to be removed is the only parameter required. array_unique() maintains the original elemental order while returning a new array that only contains the unique values from the input array.
Describe the function of the PHP array_reverse() function.
To reverse the order of entries in an array, use PHP's array_reverse() method. The array to reverse is the only parameter required. The function array_reverse() creates a new array with the contents arranged in reverse. The array's keys will be kept if the preserve_keys argument is set to true; if not, they will be reindexed numerically.
In PHP, how do you sort an array?
Depending on the sorting criteria and whether you need to preserve keys, you can sort an array in PHP using the sort(), rsort(), asort(), arsort(), ksort(), and krsort() methods. Arrays can be sorted by values in ascending or descending order using the sort() and rsort() functions, respectively. Arrays can be sorted by values while keeping their keys intact using the asort and arsort functions. Arrays can be sorted by keys in ascending or descending order using the functions ksort() and krsort().
Describe the function of PHP's explode() function.
To split a string into an array of substrings based on a defined delimiter, use PHP's explode() function. The input text to be split and the delimiter string are the two parameters required. An array with the substrings divided by the delimiter is returned by explode().
What is the PHP implode() function used for?
The answer is that you can concatenate items of an array into a single string using PHP's implode() function by placing a specified separator between each element. The array of elements to concatenate and the separator string are its two required parameters. The output of implode() is a string that has every element in the array linked together using the selected separator.
Describe the function of PHP's strpos() function.
The PHP strpos() method can be used to determine the location of a substring's first occurrence inside another string. The string to search within and the substring to look for are the two arguments required. strpos() returns the position of the first occurrence (0-based index) if the substring is located within the string; if not, it returns false.
In PHP, how can one compare strings without taking into account case?
Answer: Before employing the equality operator (==) in PHP, you can use functions like strcasecmp() or strtolower() to do a case-insensitive string comparison. When comparing two strings, the strcasecmp() function ignores case differences and returns 0 if the strings are equal, a negative number if the strings are less than each other, and a positive value if the strings are larger than each other. As an alternative, you can use strtolower() or strtoupper() to convert both strings to lowercase (or uppercase), and then use the equality operator to compare the two strings as usual.
Describe the function that PHP's file_exists() does.
The PHP method file_exists() is utilized to verify if a file or directory is present on the filesystem. The path to the file or directory to be checked is the only parameter required. File_exists() returns true if the file or directory is present; false otherwise. Before executing actions like opening or removing files, this method is frequently used to confirm their existence.
What is the function glob() in PHP used for?
To acquire an array of filenames or directory paths that match a given pattern (glob pattern), utilize PHP's glob() function. The glob pattern to compare against is the only parameter required. Character ranges ([a-z] for any character in the range) and wildcard characters (* for zero or more characters,? for a single character) can be included in the glob pattern. The array that contains the matching filenames or paths is returned by glob().
Describe the function that PHP's count() function does.
The count() PHP method counts the number of attributes in an object or the number of elements in an array. The array or object to count is the only parameter required. The number of properties in the object or the number of entries in the array is returned by count().
Describe the function that PHP's strlen() does.
To find the length of a string in PHP, use the strlen() function. The string to measure is the only parameter required. The number of characters in the string is returned by strlen().
Describe the function that PHP's strlen() does.
To find the length of a string in PHP, use the strlen() function. The string to measure is the only parameter required. The number of characters in the string is returned by strlen().
Describe the function that PHP's str_replace() serves.
To replace every instance of a search string within a provided string with a replacement string, utilize PHP's str_replace() function. Three inputs are required: the search string, the replacement string, and the string to be replaced. str_replace() yields a new string with the replacement string substituted for each instance of the search string.
In PHP, how may an HTTP header be sent?
Answer: The header() function in PHP allows you to submit an HTTP header. Sending status codes, setting cookies, and rerouting users to other pages are frequent uses for this feature. The header string to send is the only parameter required by the header() function.
Why would someone use PHP object-oriented programming (OOP)?
The answer is that the paradigm of object-oriented programming, or OOP, is centered on the idea of "objects," which are just instances of classes. OOP in PHP enables you to organize your code into reusable classes and objects, encapsulate information and actions, and establish class hierarchies using polymorphism and inheritance.
Describe the ideas behind PHP's class and object notions.
In PHP, a class serves as an object creation blueprint. It outlines the methods (functions) and characteristics (properties) that the class's objects will possess. In contrast, an object is a specific instance of a class. It symbolizes a distinct entity with unique behavior (methods) and state (property values). The class name and the new keyword are used to create objects.
What does PHP inheritance mean?
A class can inherit methods and properties from another class known as the parent or base class thanks to an object-oriented programming concept called inheritance. With PHP, the extends keyword allows a child class to extend a parent class. This encourages a hierarchical structure in the codebase of your application and allows for the reuse of code.
In PHP, how is method overriding accomplished?
The ability of a child class to provide a particular implementation of a method that is already specified in its parent class is known as method overriding. Depending on the visibility of the parent method, you can override a method in PHP by redefining it in the child class with the public, protected, or private visibility modifier.
What does PHP encapsulation mean?
The idea of combining data (properties) and methods (functions) that manipulate the data into a single entity called a class is known as encapsulation. Encapsulation in PHP is accomplished by designating class attributes as private or protected, hence limiting external parties' ability to access them directly. The getter and setter methods are then used to control access to these attributes.
Describe the PHP principles of interfaces and abstraction.
The technique of hiding a class's implementation specifics and exposing only the interfaces required to communicate with it is known as abstraction. Classes in PHP are required to abide by a contract defined by interfaces by implementing the designated methods. This encourages code flexibility and makes it possible to implement the same interface more than once.
What does PHP polymorphism mean?
The capacity of objects of various classes to be regarded as objects of a shared superclass is known as polymorphism. Polymorphism in PHP is usually accomplished by implementing interfaces and overriding methods. It makes it possible to build code that manipulates superclass objects without having to be aware of the particular subclass.
What are PHP's abstract methods and classes?
In PHP, abstract classes are those that have one or more abstract methods but are not directly instantiable. Concrete subclasses must implement abstract methods since they are declared empty. Subclasses might give specific implementations whereas an abstract class defines a common interface for a collection of related classes.
In PHP, how can one stop a class from inheriting?
In PHP, you can declare a class final to stop it from being inherited. There cannot be any subclasses in a final class. Similarly, by designating certain methods as final, you can stop them from being overridden in subclasses.
Describe the PHP constructor and destructor concepts.
In PHP, a constructor is a unique function that is invoked automatically upon creating an object of a class with the new keyword. It is employed for carrying out any setup operations or initializing object properties. Usually, constructors are defined via the magic procedure __construct(). A destructor, on the other hand, is a unique method that is invoked automatically when an object is destroyed or leaves its scope. It is defined using the magic procedure __destruct() and is used to release resources or carry out cleanup operations.
Frequently Asked Questions
How to Hire php developers India?
Establishing your project's specifications and carrying out a methodical hiring procedure are the first steps in hiring PHP developers in India. For networking purposes, make use of websites such as Upwork or LinkedIn, as well as local PHP developer communities. Examine technical proficiency, background, and cultural fit. Throughout the process, make sure there is clear communication.
What is a PHP developer?
A PHP Developer is a specialist in web development utilizing the PHP programming language and server-side scripting. They are essential to the development of dynamic web pages, database management, and server-side logic implementation that improves the operation of websites.
What is a Full stack PHP developer?
How to Hire PHP Developers for your project?
Determine the project's scope and the technical capabilities needed before hiring PHP developers. Check if their experience and portfolios align with your company's culture. Collaboration skills, problem-solving aptitude, and effective communication are critical factors to take into account when employing new employees.
Benefits of hiring php developers
Hiring PHP developers has a number of benefits, such as cost-effective solutions, flexibility, scalability, and web development experience. PHP is a popular choice for PHP development outsourcing since it is open-source, which lowers license costs, and India has a large talent pool of experienced engineers.
What are the skills sets of a good php developer
Is PHP still in demand?
PHP is in very high demand as 90% of website and web apps are build on php. Most popular framework and content Management system in the world are build on php.
How much does a Full Stack PHP programmer charge per hour?
Full stack php programmer in India charge is $15 per hour with a minimum commitment of 20 hours in a month.
How much does a PHP programmer charge per hour?
The charge of php programmer varies on the skill set and experience level. The charge of php programmer is $10 per hour
How much does it cost to hire a PHP developer?
The cost to hire php developer in India depends on the pricing plan model you choose.
How much does it cost to hire dedicated PHP developers in India?
The cost of hiring dedicated php developer is $1200 per month. Once you hire the dedicated php developer you can immediately start working with the developer.
Where can I hire a PHP developer?
When employ a PHP developer, different needs are met by different platforms and sources. There is a wide range of freelancers with different skill sets and degrees of expertise available on freelancing marketplaces like Upwork and Freelancer
There are ways to get in touch with PHP developers who are actively looking for work through job platforms like Indeed and LinkedIn. Specific PHP-related jobs are the subject of specialized job forums such as PHPClasses and PHP Jobs
The development communities on GitHub, Stack Overflow, and sites like r/forhire on Reddit are great places to interact with PHP developers working on open-source and coding projects. Businesses can interact with PHP development services or individual remote developers using outsourcing platforms like as Toptal and Clutch. Locating qualified PHP developers can also be facilitated by personal recommendations and local and virtual networking events. Think about
How to hire dedicated PHP developer?
Where can I hire a PHP developer?
You can hire php developers at BM Coder. We have been working on php from more than 20 years now and can provide you best php developers in the world. All of our php developers are experienced and well trained to work with international clients.
Is PHP in demand in India?
PHP is in very high demand in India. 90% of websites in India are build on PHP and 50% softwares are build on php. PHP is in India for more than 40 years and still very popular programming language used by corporates.
What is the rate of PHP per hour?
Starting rate of php per hour is $10 per hour with a minimum commitment of 20 hours in a month.
Why hire PHP developers?
Having PHP developers on staff has many benefits, including their proficiency with web development and server-side scripting. Because PHP is frequently used to create dynamic websites and applications, PHP developers are essential for projects that call for reliable and expandable web solutions. PHP developers make contributions to open-source projects and enhance development efficiency and economy by their expertise with PHP frameworks.
Why PHP is best for freelancing?
Because of its adaptability, popularity, and demand in the freelancing industry, PHP is the best option for independent contractors. Because it is open-source, it is more affordable for projects, which appeals to clients on a tight budget. Because of its ease of use, speed of development, and large developer community, PHP is a popular choice for freelance projects of all sizes.
Why hire dedicated PHP developers?
Employing specialized PHP developers guarantees that your project will receive focused attention, resulting in effective development and on-time delivery. Dedicated developers provide solutions that are specifically suited to your project requirements by bringing their knowledge in PHP frameworks, databases, and server-side scripting to the table. Their singular focus on your project reduces outside distractions and fosters a more efficient and cooperative development process.
How to hire remote developers India
Establishing your project's specifications and carrying out a methodical hiring procedure are the first steps in hiring remote developers in India. With the abundance of talented engineers in India, make use of sites like Upwork or LinkedIn. During interviews, assess candidates' experience, technical proficiency, and cultural fit. India's remote developers are a great option because they frequently provide affordable solutions, PHP proficiency, and efficient communication.