Here is my cheat sheet I created along my learning journey. If you have any recommendations (addition/subtraction) let me know.
<?php
//Naming convention
$first_name = 'Mike'. // all lower case with underscore separators
function updateProduct() // camelCase
class ProductItem // StudlyCaps
const ACCESS_KEY = '123abc'; // all upper case with underscore separators
//output
echo 'Hello World';
//variable declaration
$name = 'Mike'; //string
$isActive = true; //boolean
$number = 25; //integer
$amount = 99.95; //float
//string concat
echo 'Hello ' . $name;
//string escape characters \n new line \t tab \\ backslash
echo "Hello Mike\nHello David";
//string interpolation
echo "Hello $name";
//string number of characters
echo strlen($name);
// Remove space(s) before and after
echo trim($text)
// Convert to lowercase / uppercase
echo strtolower($email);
echo strtoupper($name);
// Converts the first character to uppercase
echo ucfirst($name); // 'Mike'
// Replace text a by text b in $text
echo str_replace('a', 'b', $text);
// String Contains (PHP 8)
echo str_contains($name, 'ke') # true
// Check if numeric
echo is_numeric('59.99'); # true
// Round a number
echo(round(0.80)); // returns 1
echo(round(0.49)); // returns 0
// Random number
echo(rand(10, 100)); # 89
// Ternary operator (true : false)
echo $valid ? 'user valid' : 'user not valid';
//Null Coalesce Operator
echo $name ?? 'Mike'; //output 'Mike' if $name is null
//Null Coalesce Assignment
$name ??= 'Mike';
// Null Safe Operator (PHP 8) will return null if one ? is null
echo $user?->profile?->activate();
// Null Safe + Null Coalesce (if null will return 'No user profile')
echo $user?->profile?->activate() ?? 'Not applicable';
//Spaceship operator return -1 0 1
$names = ['Mike', 'Paul', 'John']
usort($names, function($a, $b) {
return $a <=> $b;
}
// ['John', 'Mike', 'Paul']
// print variables contents (for debug)
var_dump($names);
print_r($names);
// terminate the current script
die();
//Conditionals
If ($condition == 10) {
echo 'condition 10'
} elseif ($condition == 5) {
echo 'condition 5'
} else {
echo 'all other conditions'
}
//Comparaison operation
== // equal no type check
=== // equal with type check
!= //not equal
|| //or
&& //and
> //greater than
< //less than
// Match Expression (PHP 8)
$type = match($color) {
'red' => 'danger',
'yellow', 'orange' => 'warning',
'green' => 'success',
default => 'Unknown'
};
//for loop
for ($i = 0; $i < 20; $i++) {
echo "i value = " . i;
}
//while loop
$number = 1;
while ($number < 10) {
echo 'value : ' . $number ;
$number += 1;
}
//do while
$number = 1;
do {
echo 'value : ' . $number ;
$number += 1;
} while ($number < 10);
//Array declaration
$names = ['Mike', 'Peter', 'Shawn', 'John'];
//add to array
$names[] = 'Micheal';
//Spread Operator
$names = ['Mike', 'Peter', 'Paul'];
$people = ['John', ...$names]; // ['John', 'Mike', 'Peter', 'Paul']
//Remove array entry:
unset($names['Peter']);
//Array to string
echo implode(', ', $names) //output Mike, Shawn, John, Micheal
// String to Array
echo explode(',', $text); // ['Mike', 'Shawn', 'John']
// Direct access
echo $name[1] //output Peter
//loop for each array entry
foreach($names as $name) {
echo 'Hello ' . $name;
}
// loop break / continue
$values = ['one', 'two', 'three'];
foreach ($values as $value) {
if ($value === 'two') {
break; // exit loop
} elseif ($value === 'three') {
continue; // next loop iteration
}
}
// Number of items in a Array
echo count($names);
//Associative array:
$person = ['age' => 45, 'genre' => 'men'];
//Add to ass. array:
$person['name'] = 'Mike';
//loop ass. array key => value:
foreach($names as $key => $value) {
echo $key . ' : ' . $value
}
// Check if a specific key exist
echo array_key_exist('age', $person);
// Return keys
echo array_keys($person); // ['age', 'genre']
// Return values
echo array_values($person) // [45, 'men']
//Array filter (return a filtered array)
$filtered_people = array_filter($people, function ($person) {
return $names->active;
})
// Array map (return transform array):
$only_names = array_map(function($person) {
return [‘name’ => $person->name];
}, $people)
//function declararion
function name($first_name, $last_name = 'default value') {
puts $first_name . ' ' . $last_name
}
//function call
name('Mike', 'Taylor');
//function call with named parameters (PHP 8)
name(first_name: 'Mike', last_name: 'Taylor'); // order can change
//function variables params
function name(...$params) {
return $params[0] . “ “ . params[1];
}
// Closure function
Route::get('/', function () {
return view('welcome');
});
// Arrow functions
Route::get('/', fn () => return view('welcome');
//File read
$file = fopen("test.txt", "r");
//Output lines until EOF is reached
while(! feof($file)) {
$line = fgets($file);
echo $line. "<br>";
}
fclose($file);
// File write
$file = fopen('export.csv', 'a');
$array = ['name' => 'Mike', 'age' => 45];
//Write key name as csv header
fputcsv($file, array_keys($array[0]));
//Write lines (format as csv)
foreach ($array as $row) {
fputcsv($file, $row);
}
fclose($file);
//Throw Error
if (someCondition) {
throw new Exception('Data format error');
}
//Catch the Error
try {
$db->checkData($data)
} catch (Exception as $e)
echo $e->getMessage();
}
//class declaration
class Person
{
}
// object instantiation
$person = new Person
//class properties and constructor
class Person
{
protected $first_name;
protected $last_name;
public function __construc($first_name, $last_name) {
$this->first_name = $first_name;
$this->last_name = $last_name
}
// Constructor Property Promotion (PHP 8)
class Person
{
public function __construc(protected $first_name, protected $last_name)
{
}
//static constructor
public static function create(...$params) {
return new self($params)
}
$person = Person::create(‘Mike’, ‘Taylor’);
// class inheritance
class Customer extends Person
{
public function name()
{
parent::name();
echo 'Override method';
}
}
// Static Method
class greeting {
public static function welcome() {
echo "Hello World!";
}
}
// Call static method
greeting::welcome();
// Static method internal call
class greeting {
public static function welcome() {
echo "Hello World!";
}
public function __construct() {
self::welcome();
}
}
new greeting();
// Interface
interface Animal {
public function makeSound();
}
class Cat implements Animal {
public function makeSound() {
echo "Meow";
}
}
$animal = new Cat();
$animal->makeSound();
//Trait (mix-in)
trait HelloWorld {
public function sayHello() {
echo 'Hello World!';
}
}
class Greetings {
use HelloWorld;
}
$object = new Greetings();
$object->sayHello();
My beloved PHP cheat sheet