PHP

PHP Cheat Sheet

Here's a cheat sheet summarizing some of the common PHP concepts, functions, and syntax:

php

<?php
// PHP Cheat Sheet

// Variables
$variableName = value;     // Declare a variable

// Data Types
$string = "Hello";         // String
$number = 10;              // Number
$float = 3.14;             // Float
$boolean = true;           // Boolean
$array = [1, 2, 3];        // Array
$associativeArray = [      // Associative Array
    "key1" => "value1",
    "key2" => "value2"
];
$object = new stdClass();  // Object
$object->property = value; // Add a property to an object

// Operators
$sum = $num1 + $num2;        // Addition
$difference = $num1 - $num2; // Subtraction
$product = $num1 * $num2;    // Multiplication
$quotient = $num1 / $num2;   // Division
$remainder = $num1 % $num2;  // Modulus
$isGreater = $num1 > $num2;  // Greater than
$isEqual = $num1 === $num2;  // Equality

// Conditionals
if (condition) {
    // Code executed if condition is true
}
elseif (condition2) {
    // Code executed if condition2 is true
}
else {
    // Code executed if no previous conditions are true
}

// Loops
for ($i = 0; $i < $limit; $i++) {
    // Code executed in each iteration
}

while (condition) {
    // Code executed repeatedly while condition is true
}

do {
    // Code executed at least once, then repeatedly while condition is true
} while (condition);

// Functions
function functionName($parameter1, $parameter2) {
    // Code executed by the function
    return $value;   // Optional return statement
}

// Arrays
$array = [1, 2, 3];        // Array declaration
$length = count($array);   // Length of the array
$element = $array[$index]; // Accessing an element
array_push($array, $value);      // Add an element to the end
array_pop($array);                // Remove the last element
array_unshift($array, $value);    // Add an element to the beginning
array_shift($array);              // Remove the first element
array_splice($array, $index, $count);   // Remove or replace elements

// Strings
$string = "Hello, World!";
$length = strlen($string);        // Length of the string
$uppercase = strtoupper($string); // Convert to uppercase
$lowercase = strtolower($string); // Convert to lowercase
$substring = substr($string, $start, $length);  // Extract a substring
$replacedString = str_replace($search, $replace, $string);   // Replace substring

// File Handling
$handle = fopen("file.txt", "r");     // Open file for reading
$content = fread($handle, filesize("file.txt"));   // Read file content
fclose($handle);                      // Close file

$handle = fopen("file.txt", "w");     // Open file for writing
fwrite($handle, "Content");           // Write content to file
fclose($handle);                      // Close file

// Superglobals
$_GET['parameter'];         // Access GET request parameter
$_POST['parameter'];        // Access POST request parameter
$_SESSION['variable'];      // Access session variable
$_COOKIE['variable'];       // Access cookie variable
$_SERVER['variable'];       // Access server information

// Include and Require
include 'filename.php';     // Include a PHP file
require 'filename.php';     // Require a PHP file
?>

This cheat sheet covers some of the commonly used PHP concepts, functions, syntax, variables, data types, operators, conditionals, loops, functions, arrays, strings, file handling, superglobals, and include/require statements. It serves as a handy reference for quick look-ups and reminders while working with PHP.