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Question-1. What is PHP?
Answer-1: PHP (Hypertext Preprocessor) is a server-side scripting language designed for web development.
Question-2. What are PHP's key features?
Answer-2: Key features include simplicity, platform independence, built-in support for databases, and extensibility.
Question-3. What is the difference between echo and print in PHP?
Answer-3: echo is faster and can output multiple strings; print is slower and always returns 1.
Question-4. What are PHP's data types?
Answer-4: PHP's data types include String, Integer, Float, Boolean, Array, Object, NULL, and Resource.
Question-5. What is a PHP variable?
Answer-5: A variable in PHP is used to store data, declared with a $ prefix.
Question-6. What is the difference between == and === in PHP?
Answer-6: == checks value equality; === checks both value and type equality.
Question-7. What is the purpose of the isset() function in PHP?
Answer-7: isset() checks if a variable is set and is not NULL.
Question-8. What is the difference between include and require?
Answer-8: Both include files, but require throws a fatal error if the file is not found, while include issues a warning.
Question-9. What is a PHP session?
Answer-9: A session stores data on the server to persist user information across multiple requests.
Question-10. What is the purpose of cookies in PHP?
Answer-10: Cookies store data on the client's browser to track user information.
Question-11. What are PHP superglobals?
Answer-11: Superglobals are built-in variables accessible globally, such as $_GET, $_POST, and $_SESSION.
Question-12. What is the difference between GET and POST in PHP?
Answer-12: GET appends data to the URL; POST sends data in the request body and is more secure.
Question-13. How do you connect to a database in PHP?
Answer-13: Use functions like mysqli_connect() or the PDO class for database connections.
Question-14. What is the purpose of the explode() function in PHP?
Answer-14: explode() splits a string into an array based on a specified delimiter.
Question-15. What is the implode() function in PHP?
Answer-15: implode() joins array elements into a string with a specified separator.
Question-16. What is a PHP array?
Answer-16: An array is a data structure that stores multiple values in a single variable.
Question-17. What is the difference between an indexed array and an associative array?
Answer-17: Indexed arrays use numeric keys; associative arrays use named keys.
Question-18. What is the purpose of the foreach loop in PHP?
Answer-18: foreach iterates over arrays or objects, making it ideal for collections.
Question-19. What are PHP's magic methods?
Answer-19: Magic methods are predefined methods like __construct(), __destruct(), and __get(), used for specific behaviors.
Question-20. What is a constructor in PHP?
Answer-20: A constructor is a special method (__construct) called automatically when an object is created.
Question-21. What is a destructor in PHP?
Answer-21: A destructor (__destruct) is a special method executed when an object is destroyed.
Question-22. What is the difference between static and final in PHP?
Answer-22: static denotes class-level properties or methods; final prevents further overriding.
Question-23. What is a PHP interface?
Answer-23: An interface defines method signatures that implementing classes must define.
Question-24. What is the difference between abstract class and interface?
Answer-24: Abstract classes can have method implementations; interfaces cannot (until PHP 8.0).
Question-25. What are PHP traits?
Answer-25: Traits allow the reuse of methods in multiple classes, avoiding multiple inheritance.
Question-26. How do you handle exceptions in PHP?
Answer-26: Use try, catch, and finally blocks to handle exceptions.
Question-27. What is the purpose of the throw keyword in PHP?
Answer-27: throw is used to generate an exception.
Question-28. What is the difference between isset() and empty()?
Answer-28: isset() checks if a variable is set and not NULL; empty() checks if a variable has an empty or zero value.
Question-29. What is the str_replace() function in PHP?
Answer-29: str_replace() replaces occurrences of a substring within a string.
Question-30. What is the difference between strpos() and strstr()?
Answer-30: strpos() returns the position of a substring; strstr() returns the part of the string from the first match.
Question-31. What is the purpose of the header() function in PHP?
Answer-31: header() sends raw HTTP headers to the browser.
Question-32. How do you redirect a page in PHP?
Answer-32: Use header("Location: url"); for redirection.
Question-33. What is the purpose of the die() function in PHP?
Answer-33: die() halts script execution and optionally outputs a message.
Question-34. What is the difference between mysql and mysqli?
Answer-34: mysql is deprecated; mysqli provides improved security, performance, and object-oriented support.
Question-35. What is the PDO class in PHP?
Answer-35: PDO (PHP Data Objects) is a database access layer providing a uniform way to access databases.
Question-36. What is the purpose of the serialize() function in PHP?
Answer-36: serialize() converts a value into a storable string representation.
Question-37. What is the unserialize() function in PHP?
Answer-37: unserialize() converts a serialized string back into a PHP value.
Question-38. How do you start a PHP session?
Answer-38: Use session_start(); to start a session.
Question-39. What is the purpose of the unset() function in PHP?
Answer-39: unset() destroys a variable or an array element.
Question-40. What is the difference between require_once and include_once?
Answer-40: Both include files but avoid multiple inclusions; require_once throws a fatal error if the file is missing.
Question-41. What is PHP's default file extension?
Answer-41: The default file extension for PHP files is .php.
Question-42. How do you comment code in PHP?
Answer-42: Use // for single-line comments and /* */ for multi-line comments.
Question-43. What is the define() function in PHP?
Answer-43: define() defines a constant that cannot be changed or undefined.
Question-44. What is the difference between include and include_once?
Answer-44: include_once ensures a file is included only once, even if called multiple times.
Question-45. What is the purpose of the file_get_contents() function?
Answer-45: file_get_contents() reads a file's content into a string.
Question-46. How do you upload a file in PHP?
Answer-46: Use the $_FILES array to handle file uploads and move files using move_uploaded_file().
Question-47. What is a PHP constant?
Answer-47: A constant is a value that cannot be changed after being defined, created using define() or const.
Question-48. What is the difference between var_dump() and print_r()?
Answer-48: var_dump() displays detailed variable information; print_r() displays simpler information.
Question-49. How do you encrypt data in PHP?
Answer-49: Use functions like md5(), sha1(), or libraries like OpenSSL for encryption.
Question-50. What are PHP's error types?
Answer-50: Error types include Notice, Warning, Parse Error, and Fatal Error.
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