What are the features in PHP7

type declaration< h2>

look at the code and it’s clear a glance. < p>

class person {     public function age(int $age) : string     {         return 'age is ' . $age;     } }< pre>
copy after login< div>< div> 
namespace use keyword batch 
non-mixed mode< >use publishers\packt\{ book, ebook, video}; use function publishers\packt\{ getbook, savebook }; use const publishers\packt\{ count, key };< 
mixed >use publishers\packt\{     book,     ebook,     video,     function getbook,     function savebook,     const count,     const key };< 
composite     paper\book,     electronic\ebook,     media\video 
anonymous class< 
anonymous classes are declared used same time have all functions of other classes. the difference is that anonymous no name. syntax as follows: >new class(argument) { definition };< 
anonymous names, but within php, they will be assigned globally unique name in memory reference address table. em>< >$name =" new class('You') {"     public function __construct($name)         echo $name; can inherit parent its methods. >class packt     protected $number;     public function __construct()         echo 'parent construct';     public function getnumber() : float         return $this->number; } $number =" new class(5) extends Packt"     public function __construct(float $number)         parent::__construct();         $this->number =" $number;" }; echo $number->getnumber();< interfaces. >interface publishers     public function __construct(string name, string address);     public function getname();     public function getaddress(); class packt     protected $name;     protected $address;     public function ... $info =" new class('name', 'address') extends Packt implement Publishers"     public function __construct(string $name, string $address)         $this->name =" $name;"         $this->address =" $address;"     public function getname() : string         return $this->name;     public function getaddress() : string         return $this->address; echo $info->getname() . ' ' . $info->getaddress();< nested class. >class math     public $first_number =" 10;"     public $second_number =" 10;"     public function add() : float         return $this->first_number + $this->second_number;     public function mutiply_sum()         return new class() extends math         {             public function mutiply(float $third_number) : float             {                 return $this->add() * $third_number;             }         }; $math =" new Math();" echo $math->mutiply_sum()->mutiply(2);< 
abandon old-fashioned constructor< 
starting from php4, constructor declare itself by naming it consistent with in php7, still possible to this way. use, deprecated, output deprecated information deprecated: methods their not constructors future version php; packt has ...< code>, it recommended __construct()< code> php7. 
throwable interface< 
 starting fatal errors program intercepted. php7 provides throwable interface, exceptions inherited interface. 
error< 
now most error conditions throw an instance, similar intercepted exceptions, instances try catch. >try     ... } catch(error $e)     echo $e->getmessage(); 
in some situations, only sub-instances thrown, such typeerror, divisionbyzeroerror, parseerror, etc. 
<=">Operator
" 
<=">The" operator ="=," < >< code>the three comparison operators packaged together. specific usage rules follows. 
 returns 0 when both sides equal 
 -1 left side less than right 1 greater p>< blockquote> 
null merge operator 
??< combination returned directly first operand exists, otherwise second returned. >$title =" $post['title'] ?? NULL;" $title =" $post['title'] ?? $get['title'] ?? 'No title';

uniform variable syntax< >$first =" ['name' => 'second'];" $second =" 'two';" echo $$first['name']; echo ${sfirst['name']};   php7 ... echo $object->$methods['title']; echo $object->{$methods['title']};   php7<

the main reason parsing method different previous php. just add curly braces just like above code, report error.

constant array< php5.6, constant arrays using const< keyword. through define< function. initialize. >const stores =" ['en', 'fr', 'ar']; // php5.6" define('stores', ['en', 'fr', 'ar']);   php7<

default value switch<

before multiple default values ​​were allowed switch statement. there one value, level occur. mistake. >  php7之前 switch (true) {     case 'value':         # code...         break;     default:  php7

option array session_start function< session_start() function must called session, parameters passed, session-related configurations they php.ini file. you pass parameter options calling these setting override session configuration php.ini. >session_start([     'cookie_lifetime' ="> 3600,"     'read_and_close' ="> true" ]);<

unserialize introduces filters<

unserialize() deserialize any type object without filter items, which unsafe. filters unserialize(), deserialization types objects default. >$result =" unserialize($object, ['allowed_classes' => ['Book', 'Ebook']]);

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