php -S localhost:3000

// one line comment/*This is a multiple-lines comment blockthat spans over multiplelines*/

// PHP opening/closing tag<?php  echo "Hello World";?>// if no closing tag the rest of the file will be considered PHP// Short syntax for PHP echo<?="Hello World"?>//Enable strict typing (first line of your PHP file)<?declare(strict_types=1);// Include a PHP filerequire'app/Product.php'// Create a namespacenamespaceApp;// Use a namespaceuseApp\Product;$firstName='Mike'// camelCasefunctionupdateProduct()// camelCaseclassProductItem// StudlyCapsconstACCESS_KEY='123abc';// all upper case with underscore separators

echo'Hello World';// Debug outputvar_dump($names);print_r($products);// Input from console$name=readline('What is your name : ');

$name='Mike';//string$isActive=true;//boolean$number=25;//integer$amount=99.95;//float$fruits=['orange','apple','banana']//arrayconstMAX_USERS=50;//constantdefine('MAX_USERS',50);//constant// Assign 'by reference' with the & keyword$name_2=&$name_1// Type conversion$age=(int)readline('Your age: ');echo 'Your age is'.(string)$age;echogettype($age);// intechois_int($age)// trueechois_float(12.5)// trueechois_string($name)// true

// String can use single quote$name='Mike'// or double quote$name="Mike"// Double quote string can escape characters \n = new line  \t = tab  \\ = backslashecho"Hello Mike\nHello David";// Double quote string can do interpolationecho"Hello$name";// string concatecho'Hello '.$name;// string lengthechostrlen($name);// Remove space(s) before and afterechotrim($text)// Convert to lowercase / uppercaseechostrtolower($email);echostrtoupper($name);// Converts the first character to uppercaseechoucfirst($name);// 'Mike'// Replace text a by text b in $textechostr_replace('a','b',$text);// String Contains (PHP 8)echostr_contains($name,'ke')# true// Find numeric position of first occurrence$pos=strpos($name,'k');# 2// Returns portion of string (offset / length)echosubstr($name,0,$pos);# Mi

// Shortcut addition assignment$value=10$value++// 11// or$value+=1// 11// Shortcut subtraction assignment$value=10$value--// 9// or$value-=1// 9// Check if numericechois_numeric('59.99');# true// Round a numberechoround(0.80);// returns 1// Round a number with precisionechoround(1.49356,2));// returns 1.49// Random numberecho(rand(10,100));# 89

// If / elseif / elseif($condition==10){echo'condition 10'}elseif($condition==5){echo'condition 5'}else{echo'all other conditions'}// And condition = &&if($condition===10&&$condition2===5){echo'10 and 5'}// Or condition = ||if($condition===10||$condition2===5){echo'10 or 5'}// One lineif($isActive)returntrue;// Null checkif(is_null($name)){dosomething...}//Comparaison operation==// equal no type check===// equal with type check!=//not equal||//or&&//and>//greater than<//less than// Ternary operator (true : false)echo$isValid?'user valid':'user not valid';//Null Coalesce Operatorecho$name??'Mike';//output 'Mike' if $name is null//Null Coalesce Assignment$name??='Mike';// Null Safe Operator (PHP 8) will return null if one ? is nullecho$user?->profile?->activate();// Null Safe + Null Coalesce (if null will return 'No user profile')echo$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']// Return false when convert as booleanfalse,0,0.0,null,unset,'0','',[]// Compare same variable with multiple valuesswitch($color){case'red':echo'The color is red';break;case'yellow':echo'The color is yellow';break;case'blue':echo'The color is blue';break;default:echo'The color is unknown';}// Match Expression (PHP 8)$type=match($color){'red'=>'danger','yellow','orange'=>'warning','green'=>'success',default=>'Unknown'};// Check if variable declareisset($color['red']);# true

//for loopfor($i=0;$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($number<10);// foreach with break / continue exemple$values=['one','two','three'];foreach($valuesas$value){if($value==='two'){break;// exit loop}elseif($value==='three'){continue;// next loop iteration}}

//Array declaration can contain any types$example=['Mike',50.2,true,['10','20']];//Array declaration$names=['Mike','Peter','Shawn','John'];// Direct access to a specific element$name[1]//output Peter// How to access an array in an array$example[3][1]// 20//add a element to an array$names[]='Micheal';// Array merge$array3=array_merge($array1,$array2);// Merge with spreading operator (also work with associative array)$array3=[...$array1,...$array2];// Array Concat with Spread Operator$names=['Mike','Peter','Paul'];$people=['John',...$names];// ['John', 'Mike', 'Peter', 'Paul']//Remove array entry:unset($names['Peter']);//Array to stringechoimplode(', ',$names)//output Mike, Shawn, John, Micheal// String to Arrayechoexplode(',',$text);// ['Mike', 'Shawn', 'John']//loop for each array entryforeach($namesas$name){echo'Hello '.$name;}// Number of items in a Arrayechocount($names);//Associative array declaration (key => value):$person=['age'=>45,'genre'=>'men'];//Add to ass. array:$person['name']='Mike';//loop ass. array key => value:foreach($namesas$key=>$value){echo$key.' : '.$value}// Check if a specific key existechoarray_key_exists('age',$person);// Return keysechoarray_keys($person);// ['age', 'genre']// Return valuesechoarray_values($person)// [45, 'men']//Array filter (return a filtered array)$filteredPeople=array_filter($people,function($person){return$names->active;})// Array map (return transform array):$onlyNames=array_map(function($person){return['name'=>$person->name];},$people)# Search associative array$items=[['id'=>'100','name'=>'product 1'],['id'=>'200','name'=>'product 2'],['id'=>'300','name'=>'product 3'],['id'=>'400','name'=>'product 4'],];# search all value in the 'name' column$found_key=array_search('product 3',array_column($items,'name'));# return 2

//function declararionfunctionname($firstName,$lastName='defaultvalue'){return"$firstName$lastName"}//function callname('Mike','Taylor');//function call with named parameters (PHP 8)name(firstName:'Mike',lastName:'Taylor');// order can change//function variables paramsfunctionname(...$params){return$params[0].““.params[1];}// Closure functionRoute::get('/',function(){returnview('welcome');});// Arrow functionsRoute::get('/',fn()=>view('welcome');// Typed parameter and typed returnfunctiondisplay(string$first,string$last):string{return"$first$last";}// Typed or nullfunctiondisplay(?string$name){...}// Union type (or)functiondisplay(string|int$data){...}// Intersection type (and)functioncount_and_interate(Iterator&Countable$value){...}// Return any type (mixed)functionlogInfo(string$info):mixed{...}// No return (void)functionlogInfo(string$info):void{...}

// DeclarationenumInvoiceStatus{caseSent;casePaid;caseCancelled;}// The enum can then be use as a typefunctionprintInvoiceStatus(InvoiceStatus$status){print($status->name);}printInvoiceStatus(InvoiceStatus::Sent);// Sent// enum with return value and public function exempleenumInvoiceStatus:int{caseSent=0;casePaid=1;caseCancelled=2;publicfunctiontext():string{returnmatch($this){self::Sent=>'Sent',self::Paid=>'Paid',self::Cancelled=>'Cancelled'};}}functiongetInvoiceStatus(InvoiceStatus$status){print($status->text());print($status->value);}getInvoiceStatus(InvoiceStatus::Paid);// Paid1

// Get the current dir$current_dir=__DIR__;// Check if file existif(file_exists('/posts/first.txt')){dosomestuff}// Read file content into one variable$post=file_get_contents($file);//File read$file=fopen("test.txt","r");//Output lines until EOF is reachedwhile(!feof($file)){$line=fgets($file);echo$line."<br>";}fclose($file);// File write (csv)$file=fopen('export.csv','a');$array=['name'=>'Mike','age'=>45];//Write key name as csv headerfputcsv($file,array_keys($array[0]));//Write lines (format as csv)foreach($arrayas$row){fputcsv($file,$row);}fclose($file);

//Throw Errorif(someCondition){thrownewException('Data format error');}//Catch the Errortry{$db->checkData($data);}catch(Exception$e){echo$e->getMessage();}

//class declarationclassPerson{}// object instantiation$person=newPerson//class properties and constructorclassPerson{protected$firstName;protected$lastName;publicfunction__construct($firstName,$lastName){$this->firstName=$firstName;$this->lastName=$lastName}// Constructor Property Promotion (PHP 8)classPerson{publicfunction__construct(protected$firstName,protected$lastName){}// Getter and SetterclassPerson{private$name;publicfunctionsetName($name){if(!is_string($name)){thrownewException('$name must be a string!');}$this->name=$name;}publicfunctiongetName(){return$this->name;}}// Readonly properties (PHP 8.1)classPerson{publicfunction__construct(publicreadonlystring$firstName,publicreadonlystring$lastName){}}//static constructorpublicstaticfunctioncreate(...$params){returnnewself($params)}$person=Person::create(‘Mike’,‘Taylor’);// Static Methodclassgreeting{publicstaticfunctionwelcome(){echo"Hello World!";}}// Call static methodgreeting::welcome();// Static method callclassgreeting{publicstaticfunctionwelcome(){echo"Hello World!";}publicfunction__construct(){static::welcome();}}newgreeting();// Static constantclassConnection{constMAX_USER=100;}echoConnection::MAX_USER# 100// class inheritanceclassCustomerextendsPerson{publicfunctionname(){parent::name();echo'Override method';}}// self keyword reference current class (not modify by inheritance late binding like static will be)self::welcome();// InterfaceinterfaceAnimal{publicfunctionmakeSound();}classCatimplementsAnimal{publicfunctionmakeSound(){echo"Meow";}}$animal=newCat();$animal->makeSound();//Trait (mix-in)traitHelloWorld{publicfunctionsayHello(){echo'Hello World!';}}classGreetings{useHelloWorld;}$object=newGreetings();$object->sayHello();