Business IT Support Cape Town

Basic Syntax

PHP Tags & Variables

Data Types

// Scalar types
$string = "Hello World";
$integer = 42;
$float = 3.14;
$boolean = true;

// Compound types
$array = array(1, 2, 3);
$array = [1, 2, 3]; // PHP 5.4+
$object = new stdClass();

// Special types
$null = null;
$resource = fopen("file.txt", "r");

// Type checking
var_dump($variable);
gettype($variable);
is_string($variable);
is_int($variable);
is_array($variable);

Operators

// Arithmetic
+ - * / % **

// Assignment
= += -= *= /= %= .=

// Comparison
== === != !== < > <= >= <=>

// Logical
&& || ! and or xor

// String
. (concatenation)

// Array
+ (union)

// Null coalescing (PHP 7+)
$username = $_GET['user'] ?? 'guest';

// Null coalescing assignment (PHP 7.4+)
$config['key'] ??= 'default_value';

Control Structures

Conditionals

// If statement
if ($condition) {
    // code
} elseif ($another_condition) {
    // code
} else {
    // code
}

// Ternary operator
$result = $condition ? "true" : "false";

// Switch statement
switch ($variable) {
    case 'value1':
        // code
        break;
    case 'value2':
    case 'value3':
        // code for value2 or value3
        break;
    default:
        // default code
}

Loops

// For loop
for ($i = 0; $i < 10; $i++) {
    echo $i;
}

// While loop
while ($condition) {
    // code
}

// Do-while loop
do {
    // code
} while ($condition);

// Foreach loop
foreach ($array as $value) {
    echo $value;
}

foreach ($array as $key => $value) {
    echo "$key: $value";
}

// Break and continue
break;    // exit loop
continue; // skip to next iteration

Functions

Function Definition

// Basic function
function greet($name) {
    return "Hello, " . $name;
}

// Function with default parameters
function greet($name, $greeting = "Hello") {
    return $greeting . ", " . $name;
}

// Function with type declarations (PHP 7+)
function add(int $a, int $b): int {
    return $a + $b;
}

// Variable functions
$func_name = "greet";
echo $func_name("World"); // calls greet("World")

// Anonymous functions (closures)
$closure = function($name) {
    return "Hello, " . $name;
};

// Arrow functions (PHP 7.4+)
$multiply = fn($x, $y) => $x * $y;

String Functions

String Manipulation

strlen($string)

substr($string, $start, $length)

strpos($haystack, $needle)

strrpos($haystack, $needle)

str_replace($search, $replace, $subject)

str_ireplace($search, $replace, $subject)

strtolower($string)

strtoupper($string)

ucfirst($string)

ucwords($string)

trim($string)

ltrim($string)

rtrim($string)

explode($delimiter, $string)

implode($glue, $array)

str_repeat($string, $multiplier)

str_pad($string, $length, $pad_string)

strcmp($str1, $str2)

strcasecmp($str1, $str2)

strrev($string)

Array Functions

Array Manipulation

count($array)

sizeof($array)

array_push($array, $value)

array_pop($array)

array_shift($array)

array_unshift($array, $value)

array_merge($array1, $array2)

array_slice($array, $offset, $length)

array_splice($array, $offset, $length)

array_reverse($array)

array_flip($array)

array_keys($array)

array_values($array)

array_search($needle, $haystack)

in_array($needle, $haystack)

array_key_exists($key, $array)

array_unique($array)

array_filter($array, $callback)

array_map($callback, $array)

array_reduce($array, $callback)

sort($array)

rsort($array)

asort($array)

arsort($array)

ksort($array)

krsort($array)

File System Functions

File Operations

fopen($filename, $mode)

fclose($handle)

fread($handle, $length)

fwrite($handle, $string)

fgets($handle)

fgetcsv($handle)

file_get_contents($filename)

file_put_contents($filename, $data)

file($filename)

readfile($filename)

copy($source, $dest)

rename($oldname, $newname)

unlink($filename)

file_exists($filename)

is_file($filename)

is_dir($filename)

is_readable($filename)

is_writable($filename)

filesize($filename)

filemtime($filename)

mkdir($pathname)

rmdir($dirname)

opendir($path)

readdir($handle)

scandir($directory)

glob($pattern)

Date & Time Functions

Date/Time Operations

date($format, $timestamp)

time()

mktime($hour, $minute, $second, $month, $day, $year)

strtotime($time)

gmdate($format, $timestamp)

gmmktime($hour, $minute, $second, $month, $day, $year)

microtime($get_as_float)

sleep($seconds)

usleep($micro_seconds)

DateTime Class (OOP)

// Create DateTime object
$date = new DateTime();
$date = new DateTime('2023-12-25');
$date = DateTime::createFromFormat('Y-m-d', '2023-12-25');

// Format date
echo $date->format('Y-m-d H:i:s');

// Modify date
$date->add(new DateInterval('P1D')); // Add 1 day
$date->sub(new DateInterval('P1M')); // Subtract 1 month
$date->modify('+1 week');

// Compare dates
$date1 = new DateTime('2023-01-01');
$date2 = new DateTime('2023-12-31');
$diff = $date1->diff($date2);
echo $diff->days; // Number of days difference

Math Functions

Mathematical Operations

abs($number)

ceil($value)

floor($value)

round($val, $precision)

max($values)

min($values)

rand($min, $max)

mt_rand($min, $max)

random_int($min, $max)

sqrt($arg)

pow($base, $exp)

exp($arg)

log($arg, $base)

sin($arg)

cos($arg)

tan($arg)

pi()

deg2rad($number)

rad2deg($number)

number_format($number, $decimals)

Classes & Objects

Class Definition

class Person {
    // Properties
    public $name;
    private $age;
    protected $email;
    static $count = 0;

    // Constants
    const SPECIES = 'Homo sapiens';

    // Constructor
    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
        self::$count++;
    }

    // Methods
    public function getName() {
        return $this->name;
    }

    public function setAge($age) {
        if ($age > 0) {
            $this->age = $age;
        }
    }

    // Static method
    public static function getCount() {
        return self::$count;
    }

    // Magic methods
    public function __toString() {
        return $this->name;
    }

    public function __get($property) {
        if (property_exists($this, $property)) {
            return $this->$property;
        }
    }
}

Inheritance & Interfaces

// Interface
interface Drawable {
    public function draw();
}

// Abstract class
abstract class Shape {
    abstract public function calculateArea();

    public function getInfo() {
        return "This is a shape";
    }
}

// Inheritance
class Circle extends Shape implements Drawable {
    private $radius;

    public function __construct($radius) {
        $this->radius = $radius;
    }

    public function calculateArea() {
        return pi() * pow($this->radius, 2);
    }

    public function draw() {
        echo "Drawing a circle";
    }
}

// Traits
trait Logger {
    public function log($message) {
        echo "[LOG] " . $message;
    }
}

class MyClass {
    use Logger;
}

Error Handling

Exception Handling

// Try-catch block
try {
    // Code that might throw an exception
    throw new Exception("Something went wrong");
} catch (Exception $e) {
    echo "Error: " . $e->getMessage();
} finally {
    echo "This always executes";
}

// Custom exception
class CustomException extends Exception {
    public function errorMessage() {
        return "Custom error: " . $this->getMessage();
    }
}

// Multiple catch blocks
try {
    // risky code
} catch (InvalidArgumentException $e) {
    // handle invalid argument
} catch (RuntimeException $e) {
    // handle runtime error
} catch (Exception $e) {
    // handle any other exception
}

Error Functions

error_reporting($level)

set_error_handler($callback)

trigger_error($message, $type)

error_get_last()

ini_set('display_errors', 1)

Superglobals

Global Variables

$_GET - URL parameters

$_POST - Form data

$_REQUEST - GET, POST, COOKIE

$_SESSION - Session variables

$_COOKIE - Cookie values

$_FILES - Uploaded files

$_SERVER - Server information

$_ENV - Environment variables

$GLOBALS - Global scope

Common $_SERVER Variables

$_SERVER['REQUEST_METHOD']

$_SERVER['REQUEST_URI']

$_SERVER['HTTP_HOST']

$_SERVER['SERVER_NAME']

$_SERVER['DOCUMENT_ROOT']

$_SERVER['SCRIPT_NAME']

$_SERVER['QUERY_STRING']

$_SERVER['HTTP_USER_AGENT']

$_SERVER['REMOTE_ADDR']

$_SERVER['HTTPS']

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🐘 PHP Programming Language