PHP Cheatsheet

Last Updated : 23 Jul, 2025

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.

👁 php-

PHP Cheatsheet

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 ?>.

Output

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.

Variable	Description
`$name = "PHP";`	String value
`$age = 25;`	Integer value
`$price = 9.99;`	Float (decimal number)
`$is_active = true;`	Boolean (true or false)

Output

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 $.

Feature	Description
`define()`	Defines a constant
`const` keyword	Alternative way to define constants (PHP 5.3+)
Case-sensitivity	Constants are case-sensitive by default
Global scope	Constants are accessible anywhere after declaration
No `$` symbol	Constants are written without a dollar sign

3. Magic Constants

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

Magic Constant	Description
__LINE__	Current line number of the file
__FILE__	Full path and filename of the file
__DIR__	Directory of the file
__FUNCTION__	Name of the current function
__CLASS__	Name of the current class
__TRAIT__	Name of the current trait
__METHOD__	Name of the current method
__NAMESPACE__	Name of the current namespace
ClassName::class	It gives the complete name of the class, including its namespace, as a text value (string).

4. Data Types

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

Type	Description	Example
String	Text data enclosed in quotes	`$name = "Anjali";`
Integer	Whole numbers	`$count = 10;`
Float	Decimal numbers (also called double)	`$price = 15.75;`
Boolean	True or False	`$is_valid = true;`
Array	Collection of values stored in a single variable	`$colors = ["red", "blue"];`
Object	Instance of a class with properties and methods	`$car = new Car();`
NULL	Represents a variable with no value assigned	`$empty = null;`
Resource	Special variable that holds a reference to external resources like database connections or files	`$handle = fopen("file.txt", "r");`

5. Operators

PHP operators perform operations on variables and values.

Operator Type	Description	Examples
Arithmetic	`+`, `-`, `*`, `/`, `%`	`$sum = 5 + 3;`
Assignment	`=`, `+=`, `-=`, `*=`, `/=`	`$a += 2;`
Comparison	`==`, `===`, `!=`, `!==`, `<`, `>`	`$a == $b;`
Logical	`&&`, `
Increment/Decrement	`++`, `--`	`$count++;`

Output

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.

Loop Type	Description	Syntax Example
for	Repeats a block of code a specific number of times	`for (initialization; condition; increment) { }`
while	Executes code repeatedly while the condition is true (checks condition first)	`while (condition) { }`
do-while	Executes code once, then repeats while the condition is true	`do { } while (condition);`
foreach	Iterates over each element in an array or collection	`foreach ($array as $value) { }`

Output

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.

Statement Type	Description	Syntax Example
if-else	Runs code if a condition is true; otherwise runs the else block	`if (condition) { } else { }`
elseif	Allows checking multiple conditions sequentially	`if (condition) { } elseif (condition) { } else { }`
switch	Selects one block of code to execute from many options	`switch (variable) { case value: ... break; default: ... }`

Output

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

Format	Description	Example Output
`Y`	4-digit year	1996
`m`	2-digit month (01 to 12)	10
`d`	2-digit day (01 to 31)	13
`H`	Hour in 24-hour format (00-23)	05
`i`	Minutes (00-59)	35
`s`	Seconds (00-59)	32
`D`	Day of week (Mon, Tue, etc.)	Sun
`N`	ISO-8601 numeric day of week (1 = Monday)	7

Output

2025-05-24 09:28:55

DateTime Methods

Method	Description
`format()`	Formats the date/time as a string
`getTimestamp()`	Returns the Unix timestamp
`modify()`	Alters the date/time by adding or subtracting time
`setDate()`	Sets the date (year, month, day)
`setTime()`	Sets the time (hour, minute, second)

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.

Function	Description
strlen()	Returns length of a string
strrev()	Reverses a string
strtoupper()	Converts string to uppercase
strtolower()	Converts string to lowercase
strpos()	Finds position of a substring
str_replace()	Replaces text within a string
substr()	Extracts part of a string
trim()	Trim spaces from both ends
explode()	Splits string into an array
implode()	Joins array elements into a string
`.` (concatenation)	Joins two or more strings

Output

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.

Function	Description
`array()`	Creates an array
`count()`	Returns the number of elements in an array
`array_push()`	Adds one or more elements to the end of an array
`array_pop()`	Removes the last element from an array
`array_shift()`	Removes the first element from an array
`array_unshift()`	Adds one or more elements to the beginning of an array
`array_merge()`	Merges one or more arrays
`in_array()`	Checks if a value exists in an array
`sort()`	Sorts an array
`foreach` loop PHP	Iterates over each element in an array

Output

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.

Superglobal	Description
`$_GET`	HTTP GET variables
`$_POST`	HTTP POST variables
`$_SERVER`	Server and execution environment information
`$_SESSION`	Session variables
`$_COOKIE`	HTTP cookies
`$_FILES`	Uploaded 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.

Term	Description
`class`	Defines a class
`new`	Creates an object from a class
`$this`	Refers to the current object inside the class
`public`	Property/method accessible from anywhere
`private`	Accessible only within the class
`protected`	Accessible within the class and its subclasses
`__construct`	Special method called automatically when object is created

Output

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:

Function Name	Description
`abs(x)`	Returns the absolute (positive) value of `x`
`ceil(x)`	Rounds `x` up to the nearest integer
`floor(x)`	Rounds `x` down to the nearest integer
`round(x)`	Rounds `x` to the nearest integer
`max(x, y, ...)`	Returns the highest value among the arguments
`min(x, y, ...)`	Returns the lowest value among the arguments
`sqrt(x)`	Returns the square root of `x`
`pow(x, y)`	Returns `x` raised to the power of `y`
`rand(min, max)`	Returns a random integer between `min` and `max`
`mt_rand(min, max)`	Returns a better random integer (faster and more random)
`pi()`	Returns the value of π (3.14159...)
`deg2rad(x)`	Converts degrees to radians
`rad2deg(x)`	Converts radians to degrees
`bindec(string)`	Converts binary to decimal
`decbin(number)`	Converts decimal to binary
`hexdec(string)`	Converts hexadecimal to decimal
`dechex(number)`	Converts decimal to hexadecimal
`log(x, base)`	Returns the logarithm of `x` in the given base (default is e)
`exp(x)`	Returns Euler's number raised to the power of `x`
`fmod(x, y)`	Returns the remainder (modulo) of `x ÷ y`

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.

Function Name	Description
`error_reporting()`	Sets which PHP errors are reported.
`ini_set()`	Sets configuration options at runtime (e.g., display_errors).
`trigger_error()`	Generates a user-level error/warning/notice.
`set_error_handler()`	Defines a custom function to handle errors.
`restore_error_handler()`	Restores the previous error handler function.
`set_exception_handler()`	Sets a function to handle uncaught exceptions.
`restore_exception_handler()`	Restores the previous exception handler function.

PHP Error Constants

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

Constant Name	Description
`E_ERROR`	Fatal runtime errors.
`E_WARNING`	Non-fatal run-time warnings.
`E_PARSE`	Compile-time parse errors.
`E_NOTICE`	Run-time notices indicating possible errors.
`E_CORE_ERROR`	Errors during PHP's initial startup.
`E_CORE_WARNING`	Warnings during PHP's initial startup.
`E_COMPILE_ERROR`	Fatal compile-time errors.
`E_COMPILE_WARNING`	Compile-time warnings.
`E_USER_ERROR`	User-generated error message (via `trigger_error()`).
`E_USER_WARNING`	User-generated warning message.
`E_USER_NOTICE`	User-generated notice message.
`E_STRICT`	Suggests code improvements for interoperability.
`E_RECOVERABLE_ERROR`	Catchable fatal error.
`E_DEPRECATED`	Warns about deprecated code.
`E_USER_DEPRECATED`	User-generated deprecated warning.
`E_ALL`	Reports all PHP errors (includes all above).

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.

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⇱ PHP Cheatsheet - GeeksforGeeks

PHP Cheatsheet

What is a PHP Cheatsheet?

PHP Features

1. Basic Syntax

2. Variables and Constants

Constants

3. Magic Constants

4. Data Types

5. Operators

6. Loops

7. Conditional Statements

8. Date and Time

Common Date and Time Formats

DateTime Methods

9. Strings

10. Arrays

11. Superglobals

12. Classes and Objects

Math

14. PHP Errors

PHP Error Functions

PHP Error Constants

Benefits of Using PHP Cheatsheet

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