PHP Cheatsheet

PHP stands for the Hypertext Preprocessor. It is a popular, open-source server-side scripting language designed for web development but also used as a general-purpose programming language. It is widely used to create dynamic web pages and can be embedded into HTML. PHP code is executed on the server, generating HTML that is then sent to the client.

This article provides an in-depth PHP Cheat Sheet, a must-have for every web developer.

What is a PHP Cheatsheet?

A PHP Cheatsheet is a quick reference guide that shows the most important PHP commands, syntax, and examples all in one place. It helps programmers remember how to write PHP code easily without searching through long documents.

It’s like a summary of the basic and useful PHP things you need to know.

PHP Features

Here are some of the main features of PHP:

• Server-Side Scripting – Executes on the server to generate dynamic content.
• Simple Syntax – Easy to learn with C-like syntax.
• Cross-Platform – Runs on various operating systems like Linux, Windows, and macOS.
• Embedded in HTML – Easily integrated into HTML code.
• Supports Databases – Works with MySQL, PostgreSQL, SQLite, and others.
• Rich Built-in Functions – Provides thousands of built-in web and file handling functions.
• Object-Oriented – Supports classes, inheritance, interfaces, and traits.
• Large Community – Extensive support and numerous frameworks like Laravel, Symfony.

1. Basic Syntax

PHP scripts start with <?php and end with ?>.

<?php
echo "Hello, World!";
?>

Hello, World!

2. Variables and Constants

Variables store data values. A variable starts with a $ sign followed by the name. PHP variables are dynamically typed, meaning you don’t need to declare their type.

<?php
$name = "PHP";
$age = 25;
$is_active = true;

echo $name . "\n";     // Outputs: PHP
echo $age;      // Outputs: 25
?>

PHP
25

Constants

Constants in PHP are fixed values that do not change during script execution. They are defined using define() or const. They are globally accessible and do not begin with $.

3. Magic Constants

Magic constants in PHP are built-in constants that change based on context, like file name, line number, or function name.

4. Data Types

PHP supports several data types used to store different kinds of values:

5. Operators

PHP operators perform operations on variables and values.

<?php
$a = 5;
$b = 3;

echo $a + $b . "\n";   // 8
$a++;
echo $a;        // 6
?>

8
6

6. Loops

PHP Loops are a useful feature in most programming languages. With loops you can evaluate a set of instructions/functions repeatedly until certain condition is reached.

<?php
// For Loop
echo "For Loop:\n";
for ($i = 1; $i <= 3; $i++) {
    echo "Value of i: $i\n";
}

echo "\n";

// While Loop
echo "While Loop:\n";
$j = 1;
while ($j <= 3) {
    echo "Value of j: $j\n";
    $j++;
}

echo "\n";

// Do-While Loop
echo "Do-While Loop:\n";
$k = 4;
do {
    echo "Value of k: $k\n";
    $k++;
} while ($k < 4);

echo "\n";

// Foreach Loop
echo "Foreach Loop:\n";
$colors = ["Red", "Green", "Blue"];
foreach ($colors as $color) {
    echo "Color: $color\n";
}
?>

For Loop:
Value of i: 1
Value of i: 2
Value of i: 3

While Loop:
Value of j: 1
Value of j: 2
Value of j: 3

Do-While Loop:
Value of k: 4

Foreach Loop:
Color: Red
Color: Green
Color: Blue

7. Conditional Statements

Conditional Statements is used in PHP to execute a block of codes conditionally. These are used to set conditions for your code block to run. If certain condition is satisfied certain code block is executed otherwise else code block is executed.

<?php
// If statement
$age = 20;
echo "If Statement:\n";
if ($age > 18) {
    echo "You are an adult.\n";
}

echo "\n";

// If-Else statement
$score = 40;
echo "If-Else Statement:\n";
if ($score >= 50) {
    echo "You passed.\n";
} else {
    echo "You failed.\n";
}

echo "\n";

// If-Elseif-Else statement
$marks = 75;
echo "If-Elseif-Else Statement:\n";
if ($marks >= 90) {
    echo "Grade: A\n";
} elseif ($marks >= 75) {
    echo "Grade: B\n";
} elseif ($marks >= 50) {
    echo "Grade: C\n";
} else {
    echo "Grade: F\n";
}

echo "\n";

// Switch statement
$day = "Monday";
echo "Switch Statement:\n";
switch ($day) {
    case "Monday":
        echo "Start of the week.\n";
        break;
    case "Friday":
        echo "Almost weekend.\n";
        break;
    case "Sunday":
        echo "Rest day.\n";
        break;
    default:
        echo "Just another day.\n";
}
?>

If Statement:
You are an adult.

If-Else Statement:
You failed.

If-Elseif-Else Statement:
Grade: B

Switch Statement:
Start of the week.

8. Date and Time

PHP Date and time provides powerful built-in functions and classes to work with dates and times. The main ways to handle dates are using the date() function and the DateTime class.

Common Date and Time Formats

<?php
   echo date("Y-m-d H:i:s");

?>

2025-05-24 09:28:55

DateTime Methods

9. Strings

Strings are sequences of characters used to store and manipulate text. PHP provides many built-in functions to work with strings, including concatenation, searching, replacing, slicing, and changing case.

<?php
$gfg = "GFG ";
$geeks = "stands-for-GeeksforGeeks";

// Concatenate strings
echo $gfg . $geeks . "\n";  

// Find position of substring
echo strpos($geeks, "for") . "\n";  

// Replace text
echo str_replace("FG", "fg", $gfg) . "\n"; 

// Extract substring
echo substr($geeks, 6, 3) . "\n";  

// Convert to uppercase
echo strtoupper($geeks) . "\n";  

// Split string into array and print
print_r(explode("-", $geeks));
?>

GFG stands-for-GeeksforGeeks
7
Gfg 
-fo
STANDS-FOR-GEEKSFORGEEKS
Array
(
    [0] => stands
    [1] => for
    [2] => GeeksforGeeks
)

10. Arrays

Arrays in PHP are variables that store multiple values in one single variable. They can be indexed, associative and multidimensional array.

<?php
// Indexed array
$fruits = ["apple", "banana", "cherry"];

// Add element to the end
array_push($fruits, "orange");

// Remove last element
array_pop($fruits);

// Iterate over array and print each element
foreach ($fruits as $fruit) {
    echo $fruit . "\n";
}

// Associative array
$person = [
    "name" => "GFG",
    "age" => 30
];

// Print associative array element
echo $person["name"] . "\n";  
?>

apple
banana
cherry
GFG

11. Superglobals

PHP superglobals are built-in variables accessible everywhere, holding data like form input, sessions, cookies, server info, and files.

12. Classes and Objects

In PHP, a Class is a blueprint for creating objects. It groups variables (properties) and functions (methods) into a single unit.

An object is an instance of a class. It allows you to access the class’s properties and methods.

<?php
// Define a class
class Car {
    // Property
    public $brand;

    // Constructor
    public function __construct($brand) {
        $this->brand = $brand;
    }

    // Method
    public function displayBrand() {
        echo "The car brand is: " . $this->brand;
    }
}
// Create an object of the class
$myCar = new Car("Toyota");
// Call the method
$myCar->displayBrand();
?>

The car brand is: Toyota

Math

PHP offers numerous mathematical functions that allow you to perform operations like rounding, trigonometry, logarithms, and more. Here are the most commonly used functions:

14. PHP Errors

PHP Errors occur when something goes wrong while a script is running. Errors help developers identify and fix problems in the code.
There are different types of errors depending on the nature of the issue. Majorly there are the four types of the errors:

• Syntax Error or Parse Error
• Fatal Error
• Warning Error
• Notice Error

PHP Error Functions

PHP Error Functions manage how errors are reported, displayed, logged, or handled using built-in or custom error-handling mechanisms.

PHP Error Constants

PHP error constants represent different error types like warnings, notices, and fatal errors, allowing developers to control error reporting behavior.

Benefits of Using PHP Cheatsheet

Below are some key benefits of a PHP Cheatsheet:

• Faster Development: A PHP Cheat Sheet helps programmers quickly find the right code or syntax, so they can write programs faster without wasting time searching.
• Complete Reference: It includes common PHP commands, functions, and examples, which is useful for both beginners learning PHP and experienced developers needing a quick reminder.
• Build Dynamic Websites: PHP Cheat Sheet helps create interactive and dynamic web pages by providing easy access to PHP functions for working with forms, databases, and user input.
• Works Well with Other Web Technologies: PHP often works together with HTML, CSS. The cheat sheet helps understand how PHP fits in the whole web development process.
• Better Code Quality: Using the right PHP functions and syntax from the cheat sheet helps write cleaner, more reliable code.
• Handles Web Tasks Easily: The cheat sheet covers important tasks like working with files, sessions, and error handling, making websites more efficient and user-friendly.

Recommended Links:

• PHP Tutorial
• PHP Introduction
• PHP Projects for Beginners
• PHP Interview Questions