PHP Cheat Sheet
A searchable, printable PHP 8.3+ reference — syntax, strings, arrays, functions, classes, enums, attributes and modern features. Free.
Basics & types
10declare(strict_types=1);
Enforce strict scalar type checks
$x = 1;
Variables start with a dollar sign
const MAX = 100;
Compile-time constant
gettype($x)
Get the type of a value
(int) $x
Cast to an integer
is_int($x)
Type-check helper (is_string, ...)
int|string $x
Union type declaration
?string $x
Nullable type (string or null)
$a ?? 'default'
Null coalescing operator
$a ??= 'default'
Assign only if null
Strings
11"Hello $name"
Double quotes interpolate variables
'literal $x'
Single quotes are literal
$a . $b
Concatenate strings
strlen($s)
Byte length of a string
str_contains($s, 'a')
Check for a substring
str_starts_with($s, 'a')
Check the prefix
substr($s, 0, 3)
Extract part of a string
str_replace('a', 'b', $s)
Replace all occurrences
explode(',', $s)
Split into an array
sprintf('%05.2f', $n)
Formatted string output
trim($s)
Strip surrounding whitespace
Arrays
11$a = [1, 2, 3];
Indexed array literal
$a = ['k' => 'v'];
Associative array
array_map(fn($x) => $x * 2, $a)
Transform each element
array_filter($a, fn($x) => $x > 0)
Keep matching elements
array_reduce($a, $fn, 0)
Reduce to a single value
in_array($v, $a, true)
Strict value check
array_keys($a)
Get all keys
array_merge($a, $b)
Merge arrays
[...$a, ...$b]
Spread/merge arrays
count($a)
Number of elements
[$x, $y] = $a;
Array destructuring
Functions
9function f(int $a): int {}
Typed parameters and return
function f(int $a = 1) {}
Default parameter value
function f(int ...$nums) {}
Variadic parameters
f(...$args)
Spread arguments
f(name: 'Sam', age: 30)
Named arguments
$fn = fn($x) => $x + 1;
Arrow function (auto-captures scope)
function () use ($x) {}
Closure capturing a variable
$fn = strlen(...);
First-class callable syntax
function f(): never {}
Never returns (throws or exits)
Control flow
9if ($a) {} elseif ($b) {} else {}
Conditional branches
$a ? $b : $c
Ternary expression
$a ?: $b
Short ternary (falsy fallback)
match ($x) { 1, 2 => 'a', default => 'b' }
Strict, expression-based match
switch ($x) { case 1: break; }
Loose multi-way branch
foreach ($a as $k => $v) {}
Iterate keys and values
for ($i = 0; $i < 10; $i++) {}
Counted loop
while ($cond) {}
Loop while a condition holds
break / continue
Exit or skip a loop iteration
Classes & OOP
10class A extends B implements C {}
Inheritance and interfaces
public function __construct(private int $id) {}
Constructor property promotion
public readonly string $name;
Immutable after initialization
public function f(): static {}
Return the late-bound type
static::create()
Late static binding
$obj?->method()
Null-safe method call
abstract class A {}
Cannot be instantiated directly
trait T {} use T;
Reusable horizontal code
$obj instanceof A
Type check at runtime
A::class
Fully-qualified class name string
Enums
9enum Status { case Active; case Draft; }
Pure enumeration
enum Status: string { case A = 'a'; }
Backed enum (string/int)
Status::Active
Reference an enum case
Status::from('a')
Build from a backing value
Status::tryFrom('x')
Returns null if invalid
Status::cases()
Array of all cases
$status->value
Backing value of a case
$status->name
Name of the case
enum E { public function label() {} }
Enums can have methods
Error handling
9try {} catch (Throwable $e) {}
Catch errors and exceptions
catch (TypeError | ValueError $e)
Catch multiple types
catch (Exception)
Non-capturing catch (no variable)
finally {}
Always runs after try/catch
throw new RuntimeException('x')
Throw an exception
throw $e;
Re-throw the caught exception
$x = $v ?? throw new Error();
Throw as an expression
$e->getMessage()
Read the error message
$e->getPrevious()
Get the chained exception
Attributes & modern
9#[Attribute] class Route {}
Declare a custom attribute
#[Route('/home')]
Apply an attribute to a target
new ReflectionClass($x)
Inspect a class via reflection
$ref->getAttributes()
Read declared attributes
json_encode($data)
Serialize to JSON
json_decode($s, true)
Decode JSON to an array
array_is_list($a)
True if keys are 0..n in order
str_word_count($s)
Count words in a string
$obj::class
Class name from an instance
No entry matches “:q”.
About PHP Cheat Sheet
This PHP cheat sheet condenses modern PHP into one searchable page: basics and types, strings, arrays, functions, control flow, classes and OOP, enums, error handling, and attributes and other modern features. Every row is a runnable snippet with a plain-English description.
It targets PHP 8.3+, so you will find the features that define current PHP — enums, readonly properties, constructor property promotion, named arguments, match expressions, arrow functions, nullsafe calls and attributes — alongside the everyday string and array functions you reach for constantly.
The page is free and fully client-side: search filters the rows as you type, the sticky section menu jumps you around the sheet, one click copies any snippet, and a print button turns it into a paper PHP reference.
How to use PHP Cheat Sheet
- Scan the table of contents — from Basics & types to Enums, Error handling and Attributes & modern.
- Type a function name or keyword into the search box to filter the whole sheet instantly.
- Jump to a section like Classes & OOP via the sticky sidebar navigation.
- Click any snippet or its copy icon to copy the PHP code to your clipboard.
- Hit Print if you want the entire reference on paper.
Frequently asked questions
It is written for PHP 8.3 and newer. Sections on enums, attributes and modern features cover readonly properties, constructor promotion, match expressions, named arguments and nullsafe calls in addition to classic syntax.
Nine sections: basics and types, strings, arrays, functions, control flow, classes and OOP, enums, error handling, and attributes plus modern features — the parts of PHP you use daily in real projects.
Use the search box at the top. It filters every row live across all sections and shows a match count, so typing something like array_map narrows the sheet to the relevant snippets instantly.
Yes. Click the code itself or the hover copy icon and the snippet lands on your clipboard, confirmed by a short “Copied!” flash.
Yes, entirely free. It renders in your browser, needs no account and can be printed as often as you like.
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