Question 1

How to install PHP on Windows?

Accepted Answer

1) Download PHP from php.net (Thread Safe for Apache). 2) Extract to C:\php. 3) Rename php.ini-development to php.ini. 4) Add C:\php to PATH. 5) Restart the terminal, check: php -v. 6) Alternative: XAMPP or Laragon.

Question 2

How to install PHP on Mac?

Accepted Answer

1) Homebrew: brew install php. 2) Check: php -v. 3) Configuration: php --ini. 4) For different versions: brew install php@8.2. 5) Switching: brew link php@8.2.

Question 3

How to install PHP on Linux?

Accepted Answer

1) Ubuntu/Debian: sudo apt install php. 2) With modules: sudo apt install php-mysql php-mbstring php-xml. 3) CentOS: sudo yum install php. 4) Check: php -v. 5) Configuration: /etc/php/8.x/.

Question 4

What is php.ini?

Accepted Answer

1) Main PHP configuration file. 2) Location: php --ini. 3) Main settings: memory_limit, upload_max_filesize. 4) display_errors for development. 5) Restart the web server after changes.

Question 5

How to run a PHP script?

Accepted Answer

1) Command line: php script.php. 2) Built-in server: php -S localhost:8000. 3) Via Apache/Nginx. 4) Interactive mode: php -a. 5) Execute code: php -r 'echo "Hello";'.

Question 6

What data types are in PHP?

Accepted Answer

1) Scalar: bool, int, float, string. 2) Compound: array, object, callable, iterable. 3) Special: resource, NULL. 4) PHP is weakly typed. 5) Type hints for strictness.

Question 7

What is the difference between == and ===?

Accepted Answer

1) == is loose comparison with type juggling. 2) '5' == 5 returns true. 3) === is strict comparison of value AND type. 4) '5' === 5 returns false. 5) It is recommended to use ===.

Question 8

What is the difference between require and include?

Accepted Answer

1) include — Warning on error, script continues. 2) require — Fatal Error, script stops. 3) include_once/require_once — include only once. 4) require for critical files. 5) include for optional files.

Question 9

What are variables in PHP?

Accepted Answer

1) Start with $. 2) Case-sensitive: $name !== $Name. 3) Do not require type declaration. 4) Can change type dynamically. 5) Global variables: $GLOBALS, $_GET, $_POST.

Question 10

What are constants in PHP?

Accepted Answer

1) define('NAME', 'value') — old way. 2) const NAME = 'value' — modern. 3) Do not start with $. 4) Cannot be changed after definition. 5) Class constants: Class::CONST.

Question 11

How do if/else conditions work?

Accepted Answer

1) if (condition) { code }. 2) elseif for additional conditions. 3) else for the rest. 4) Ternary: $x = $a ? $b : $c. 5) Null coalescing: $x = $a ?? 'default'.

Question 12

What loops are available in PHP?

Accepted Answer

1) for ($i = 0; $i < 10; $i++). 2) while (condition). 3) do...while — at least 1 iteration. 4) foreach ($arr as $key => $val). 5) break — exit, continue — next iteration.

Question 13

How to declare a function?

Accepted Answer

1) function name($param) { return $result; }. 2) Default values: function f($x = 10). 3) Type hints: function f(int $x): string. 4) Anonymous: $fn = function() {}. 5) Arrow functions: fn($x) => $x * 2.

Question 14

What is variable scope?

Accepted Answer

1) Local — inside a function. 2) Global — outside functions. 3) global $var — access to global. 4) static — retains value between calls. 5) $GLOBALS['var'] — alternative to global.

Question 15

How to work with strings?

Accepted Answer

1) Single quotes: 'text'. 2) Double quotes: "$var inside". 3) Heredoc: <<<EOT multi-line EOT;. 4) Concatenation: $a . $b. 5) Functions: strlen(), substr(), strpos().

Question 16

How to work with arrays?

Accepted Answer

1) Indexed: [1, 2, 3]. 2) Associative: ['key' => 'value']. 3) Multidimensional: array of arrays. 4) Functions: count(), array_push(), array_merge(). 5) Sorting: sort(), asort(), ksort().

Question 17

What are superglobal variables?

Accepted Answer

1) $_GET — URL parameters. 2) $_POST — form data. 3) $_SESSION — session data. 4) $_COOKIE — cookies. 5) $_FILES — uploaded files. 6) $_SERVER — server information.

Question 18

How to process forms?

Accepted Answer

1) Form method: GET or POST. 2) $_POST['field_name'] to retrieve. 3) Validation: filter_var(), htmlspecialchars(). 4) Check: isset(), empty(). 5) CSRF tokens for security.

Question 19

How do echo and print work?

Accepted Answer

1) echo — output, no return value. 2) print — returns 1, slightly slower. 3) echo 'a', 'b' — multiple arguments. 4) print only one argument. 5) Short tag: <?= $var ?>.

Question 20

What are comments in PHP?

Accepted Answer

1) Single-line comments: // comment. 2) Single-line comments: # comment. 3) Multi-line comments: /* ... */. 4) PHPDoc: /** @param type $name */. 5) Comment why, not what.

Question 21

How to work with JSON in PHP?

Accepted Answer

1) Encoding: json_encode($array, JSON_UNESCAPED_UNICODE). 2) Decoding: json_decode($json, true). 3) true for associative array. 4) Error checking: json_last_error(). 5) For API: header('Content-Type: application/json').

Question 22

How to work with date and time?

Accepted Answer

1) date('Y-m-d H:i:s') — formatting. 2) time() — Unix timestamp. 3) strtotime('next Monday'). 4) DateTime class: new DateTime(). 5) DateInterval for differences.

Question 23

What is the DateTime class?

Accepted Answer

1) new DateTime() — current time. 2) new DateTime('2024-01-15'). 3) $dt->format('Y-m-d'). 4) $dt->modify('+1 day'). 5) $dt1->diff($dt2) — difference.

Question 24

How to work with files?

Accepted Answer

1) file_get_contents() — read. 2) file_put_contents() — write. 3) fopen(), fread(), fwrite(), fclose(). 4) file_exists() — check. 5) unlink() — delete.

Question 25

How to upload a file to the server?

Accepted Answer

1) Form: enctype='multipart/form-data'. 2) $_FILES['input_name']. 3) Error check: $_FILES['file']['error']. 4) move_uploaded_file() for saving. 5) Validate type and size.

Question 26

How to work with directories?

Accepted Answer

1) scandir() — list files. 2) mkdir() — create. 3) rmdir() — delete empty. 4) is_dir() — check. 5) glob('*.php') — pattern search.

Question 27

What is serialization?

Accepted Answer

1) serialize() — object to string. 2) unserialize() — back. 3) For saving to file/DB. 4) JSON is preferable for exchange. 5) __sleep(), __wakeup() — magic methods.

Question 28

How to work with regular expressions?

Accepted Answer

1) preg_match() — search. 2) preg_match_all() — all matches. 3) preg_replace() — replace. 4) preg_split() — split. 5) Modifiers: i, s, m, u.

Question 29

How to send an email in PHP?

Accepted Answer

1) mail() — basic, unreliable. 2) PHPMailer — recommended. 3) composer require phpmailer/phpmailer. 4) SMTP configuration for reliability. 5) SwiftMailer/Symfony Mailer — alternatives.

Question 30

How to work with cURL?

Accepted Answer

1) curl_init() — initialization. 2) curl_setopt() — options. 3) curl_exec() — execution. 4) curl_close() — closing. 5) CURLOPT_RETURNTRANSFER = true for getting the response.

Question 31

How to send an HTTP request?

Accepted Answer

1) file_get_contents() with context. 2) cURL for complex requests. 3) Guzzle HTTP — popular library. 4) composer require guzzlehttp/guzzle. 5) Symfony HTTP Client — alternative.

Question 32

How to parse XML?

Accepted Answer

1) simplexml_load_string() — simple. 2) simplexml_load_file(). 3) DOMDocument — more powerful. 4) XMLReader — for large files. 5) XPath for searching.

Question 33

How to parse HTML?

Accepted Answer

1) DOMDocument::loadHTML(). 2) DOMXPath for searching. 3) libxml_use_internal_errors(true). 4) Simple HTML DOM Parser — library. 5) Symfony DomCrawler — modern.

Question 34

How to generate PDF?

Accepted Answer

1) TCPDF — popular library. 2) FPDF — simple. 3) mPDF — supports UTF-8. 4) Dompdf — HTML to PDF. 5) composer require dompdf/dompdf.

Question 35

How to work with images?

Accepted Answer

1) GD library — built-in. 2) imagecreatefromjpeg(), imagepng(). 3) Intervention Image — convenient wrapper. 4) Imagick — more powerful, requires installation. 5) Resize, crop, watermarks.

Question 36

How to work with CSV?

Accepted Answer

1) fgetcsv() — read line. 2) fputcsv() — write line. 3) array_map(function($v){return str_getcsv($v);}, file('data.csv')). 4) League\Csv — library. 5) Encoding: mb_convert_encoding().

Question 37

How to work with Excel?

Accepted Answer

1) PhpSpreadsheet — standard. 2) composer require phpoffice/phpspreadsheet. 3) Reading: IOFactory::load(). 4) Writing: new Spreadsheet(). 5) Support for xlsx, xls, csv.

Question 38

How to generate QR codes?

Accepted Answer

1) chillerlan/php-qrcode. 2) endroid/qr-code. 3) composer require endroid/qr-code. 4) Output as PNG, SVG. 5) Customize size and logo.

Question 39

How to work with ZIP archives?

Accepted Answer

1) ZipArchive class. 2) $zip->open('file.zip', ZipArchive::CREATE). 3) $zip->addFile(). 4) $zip->extractTo(). 5) $zip->close().

Question 40

How to cache data?

Accepted Answer

1) APCu — in memory. 2) Memcached — distributed. 3) Redis — persistent. 4) File cache — simple. 5) Symfony Cache — abstraction.

Question 41

What is OOP in PHP?

Accepted Answer

1) Object-oriented programming. 2) Classes and objects. 3) Encapsulation, inheritance, polymorphism. 4) Access modifiers. 5) Interfaces and abstract classes.

Question 42

How to create a class?

Accepted Answer

1) class ClassName { }. 2) Properties: public $name;. 3) Methods: public function method() { }. 4) Constructor: __construct(). 5) Creating an instance: $obj = new ClassName().

Question 43

What are access modifiers?

Accepted Answer

1) public — accessible everywhere. 2) protected — class and subclasses. 3) private — only within the class. 4) PHP 8.1+: readonly properties. 5) Default is public.

Question 44

How does inheritance work?

Accepted Answer

1) class Child extends Parent. 2) Inherits properties and methods. 3) parent::method() — call to parent. 4) Overriding methods. 5) PHP supports only single inheritance.

Question 45

What are interfaces?

Accepted Answer

1) interface Name { public function method(); }. 2) Contract without implementation. 3) class X implements Interface. 4) Multiple implementations allowed. 5) All methods are public.

Question 46

What are abstract classes?

Accepted Answer

1) abstract class Name { }. 2) Cannot instantiate. 3) Can contain implementation. 4) abstract function — without implementation. 5) Subclasses must implement abstract methods.

Question 47

What are traits?

Accepted Answer

1) trait Name { methods }. 2) use TraitName; inside class. 3) Solve multiple inheritance problem. 4) Multiple traits can be used. 5) Conflicts are explicitly resolved.

Question 48

What are static properties and methods?

Accepted Answer

1) static $property, static function. 2) Call: ClassName::method(). 3) self:: inside class. 4) static:: late static binding. 5) Do not require object instantiation.

Question 49

What are magic methods?

Accepted Answer

1) __construct — constructor. 2) __destruct — destructor. 3) __get, __set — access to properties. 4) __call — call to undefined methods. 5) __toString — string conversion.

Question 50

What is final?

Accepted Answer

1) final class — cannot be inherited. 2) final function — cannot be overridden. 3) For protection against modifications. 4) Immutable objects are often final. 5) Use consciously.

Question 51

What is a namespace?

Accepted Answer

1) namespace App\Models;. 2) Allows avoiding name conflicts. 3) use App\Models\User;. 4) Full name: \App\Models\User. 5) PSR-4 — autoloading by namespace.

Question 52

How does autoloading work?

Accepted Answer

1) spl_autoload_register(). 2) PSR-4 standard. 3) Composer autoload. 4) namespace = path to file. 5) require 'vendor/autoload.php'.

Question 53

What is Dependency Injection?

Accepted Answer

1) Passing dependencies through constructor/methods. 2) Instead of creating inside the class. 3) Simplifies testing. 4) DI containers automate. 5) Inversion of control.

Question 54

What is late static binding?

Accepted Answer

1) static:: instead of self::. 2) Uses the calling class, not the definition. 3) Important in inheritance. 4) get_called_class(). 5) For factory methods.

Question 55

How to clone an object?

Accepted Answer

1) $copy = clone $object. 2) __clone() for customization. 3) Shallow copy by default. 4) Deep — manually clone nested objects. 5) Difference with = (assignment by reference).

Question 56

What are anonymous classes?

Accepted Answer

1) $obj = new class { }. 2) PHP 7.0+. 3) For one-time implementations. 4) Can inherit and implement interfaces. 5) Used in tests, mocks.

Question 57

What is an enum in PHP?

Accepted Answer

1) PHP 8.1+. 2) enum Status { case Pending; case Active; }. 3) Backed enums: enum Status: string { case Pending = 'pending'; }. 4) Type-safe enumerations. 5) Methods can be added.

Question 58

What are readonly properties?

Accepted Answer

1) PHP 8.1+. 2) readonly public string $name;. 3) Set only once. 4) PHP 8.2: readonly class. 5) For immutable objects.

Question 59

What is constructor property promotion?

Accepted Answer

1) PHP 8.0+. 2) public function __construct(public string $name). 3) Declaring property in constructor. 4) Less boilerplate code. 5) Works with access modifiers.

Question 60

What is the Singleton pattern?

Accepted Answer

1) Only one instance of the class. 2) private __construct(). 3) static getInstance(). 4) Difficult to test. 5) Often considered an anti-pattern.

Question 61

How to connect to MySQL?

Accepted Answer

1) PDO: new PDO('mysql:host=localhost;dbname=test', 'user', 'pass'). 2) MySQLi: new mysqli(). 3) PDO is preferable. 4) Charset: charset=utf8mb4. 5) try/catch for errors.

Question 62

How to execute a PDO query?

Accepted Answer

1) $pdo->query() — without parameters. 2) $pdo->prepare() + execute() — with parameters. 3) fetch() — one row. 4) fetchAll() — all rows. 5) Modes: FETCH_ASSOC, FETCH_OBJ.

Question 63

What are prepared statements?

Accepted Answer

1) $stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?'). 2) $stmt->execute([$id]). 3) Protection against SQL injections. 4) Parameterized queries. 5) Named: :name.

Question 64

How to protect against SQL injections?

Accepted Answer

1) ALWAYS use prepared statements. 2) NEVER concatenate input. 3) PDO or MySQLi with parameters. 4) Input validation. 5) Minimal database permissions.

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