Home > Article > Backend Development > Understanding and comparing new features of php7
1. null coalescing operator (??)
?? Syntax: If the variable exists And the value is not NULL, it will return its own value, otherwise it will return its second operand.
//php7以前 if判断 if(empty($_GET['param'])) { $param = 1; }else{ $param = $_GET['param']; } //php7以前 三元运算符 $param = empty($_GET['param']) ? 1 : $_GET['param']; //PHP7 null合并运算符 $param = $_GET['param'] ?? 1;//1
2. define() defines a constant array
//php7以前 define("CONTENT", "hello world"); echo CONTENT;//hello world //PHP7 define('ANIMALS', [ 'dog', 'cat', 'bird' ]); echo ANIMALS[2];//bird //PHP7 类外也可使用const来定义常量 const CONSTANT = 'Hello World'; echo CONSTANT;//Hello World
3. Combined comparison operators (<=>)
The combined comparison operator is used to compare two expressions. It returns -1, 0 or 1 respectively when $a is less than, equal to or greater than $b. The principle of comparison is to follow the general comparison rules of PHP.
/整数 echo 1 <=> 1; // 0 echo 1 <=> 2; // -1 echo 2 <=> 1; // 1 //浮点数 echo 1.5 <=> 1.5; // 0 echo 1.5 <=> 2.5; // -1 echo 2.5 <=> 1.5; // 1 //字符串 echo "a" <=> "a"; // 0 echo "a" <=> "b"; // -1 echo "b" <=> "a"; // 1
4. Variable type declaration
Two modes: forced (default) and strict mode. The following type parameters can be used: string, int, float, bool
//... 操作符: 表示这是一个可变参数. php5.6及以上的版本可使用: 函数定义的时候变量前使用. function intSum(int ...$ints){ return array_sum($ints); } var_dump(intSum(2,'3.5'));//5 //严格模式 //模式声明:declare(strict_types=1); 默认情况值为0,值为1代表为严格校验的模式 declare(strict_types=1); function add(int $a,int $b){ return $a+$b; } var_dump(add(2,'3.5')); //Fatal error: Uncaught TypeError: Argument 2 passed to add() must be of the type integer
5. Return value type declaration
Add support for return type declaration. Similar to parameter type declaration. (For usage, add: type name after the function definition)
//有效的返回类型 declare(strict_types = 1); function getInt(int $value): int { return $value; } print(getInt(6));//6
//无效返回类型 declare(strict_types = 1); function getNoInt(int $value): int { return $value+'2.5'; } print(getNoInt(6));//Fatal error: Uncaught TypeError: Return value of getNoInt() must be of the type integer
6. Anonymous class
Allows new class {} to create a Anonymous object.
<?php //php7以前 接口实现 interface User{ public function getDiscount(); } class VipUser implements User{ //折扣系数 private $discount = 0.6; public function getDiscount() { return $this->discount; } } class Goods{ private $price = 200; private $objectVipUser; //User接口VipUser类实现 public function getUserData($User){ $this->objectVipUser = $User; $discount = $this->objectVipUser->getDiscount(); echo "商品价格:".$this->price*$discount; } } $display = new Goods(); //常规实例化接口实现对象 $display ->getUserData(new VipUser);//商品价格:120
<?php //php7 创建一个匿名的对象 interface User{ public function getDiscount(); } class Goods{ private $price = 200; private $objectVipUser; public function getUserData($User){ $this->objectVipUser = $User; $discount = $this->objectVipUser->getDiscount(); echo "商品价格:".$this->price*$discount; } } $display = new Goods(); //new匿名对象实现user接口 $display ->getUserData(new class implements User{ private $discount = 0.6; public function getDiscount() { return $this->discount; } });//商品价格:120
7. Closure::call()
The Closure::call() method was added as a short way to temporarily bind an object scope to a closure and call it. Its performance is much faster compared to PHP5's bindTo. .
<?php //php7以前 class A { private $attribute = 'hello world'; } $getClosure = function(){ return $this->attribute; }; $getAttribute = $getClosure->bindTo(new A, 'A');//中间层闭包 echo $getAttribute();//hello world
<?php //PHP7 class A { private $attribute = 'hello world'; } $getClosure = function(){ return $this->attribute; }; echo $getClosure->call(new A);//hello world
8. unserialize()
unserialize() function: The filtering feature can prevent code injection of illegal data and provide safer deserialized data
<?php class A{ public $name = 'admin_a'; } class B{ public $name = 'admin_b'; } $objA = new A(); $objB = new B(); $serializedObjA = serialize($objA); $serializedObjB = serialize($objB); //默认行为是接收所有类; 第二个参数可以忽略 $dataA = unserialize($serializedObjA , ["allowed_classes" => true]); var_dump($dataA);//object(A)#3 (1) { ["name"]=> string(7) "admin_a" } //如果allowed_classes设置为false,unserialize会将所有对象转换为__PHP_Incomplete_Class对象 $dataA = unserialize($serializedObjA , ["allowed_classes" => false]); var_dump($dataA);//object(__PHP_Incomplete_Class)#4 (2) { ["__PHP_Incomplete_Class_Name"]=> string(1) "A" ["name"]=> string(7) "admin_a" } //转换所有对象到 __PHP_Incomplete_Class对象,除了对象"B" $dataB = unserialize($serializedObjB , ["allowed_classes" => ["B"]]); var_dump($dataB);//object(B)#3 (1) { ["name"]=> string(7) "admin_b" }
9. IntlChar
IntlChar: Provides access to some utility methods that can be used to access Unicode character information . Note: Intl extension must be installed to use!
var_dump(IntlChar::CODEPOINT_MAX);//int(1114111) echo '<br>'; var_dump(IntlChar::charName('+'));//string(9) "PLUS SIGN" echo '<br>'; var_dump(IntlChar::ispunct('?'));//bool(true)
10. CSPRNG
The CSPRNG function provides a simple mechanism to generate cryptographic random numbers.
random_bytes() - Cryptographically protected pseudo-random string.
random_int() - A cryptographically protected pseudo-random integer.
$bytes = random_bytes(8); echo(bin2hex($bytes));//随机2073a110a2e3c497 echo '<br>'; echo(random_int(1, 999));//随机786 echo '<br>'; print(random_int(-999, -1));//随机-357
11. use statement
You can use a single use statement to import classes, functions and constants from the same namespace instead of using multiple use statements.
//PHP7之前 use some\namespace\ClassA; use some\namespace\ClassB; use some\namespace\ClassC as C; use function some\namespace\fn_a; use function some\namespace\fn_b; use function some\namespace\fn_c; use const some\namespace\ConstA; use const some\namespace\ConstB; use const some\namespace\ConstC; // PHP7之后 use some\namespace\{ClassA, ClassB, ClassC as C}; use function some\namespace\{fn_a, fn_b, fn_c}; use const some\namespace\{ConstA, ConstB, ConstC};
12. intp
Newly added intp() function, receiving two parameters, the return value is the value of the first parameter divided by the second parameter and rounded.
##
echo intp(8,4);//2 echo intp(10,4);//2 echo intp(5,10);//0
13. PHP7 error handling
PHP7 改变了大多数错误的报告方式.不同于PHP5的传统错误报告机制,现在大多数错误被作为Error异常抛出.
这种Error异常可以像普通异常一样被try / catch块所捕获. 如果没有匹配的try / catch块,则调用异常处理函数(由 set_exception_handler() 注册)进行处理. 如果尚未注册异常处理函数,则按照传统方式处理:被报告为一个致命错误(Fatal Error).
Error类并不是从Exception类扩展出来的,所以用catch (Exception $e) { ... } 这样的代码是捕获不到Error的.你可以用 catch (Error $e) { ... } 这样的代码, 或者通过注册异常处理函数( set_exception_handler())来捕获Error.
<?php //php7以前 自定义异常处理 class getException extends Exception{ public function errorMsg(){ return '错误的信息'.$this->getMessage().'<br>错误的代码'.$this->getCode(); } } try { $num =10; if($num > 1) { throw new getException($num,404); } } catch (getException $e) { echo $e->errorMsg(); }
<?php //php7 异常处理 try { test(); }catch(Error $e) { echo $e->getMessage();//Call to undefined function test() }Related recommendations: "
PHP Tutorial"
The above is the detailed content of Understanding and comparing new features of php7. For more information, please follow other related articles on the PHP Chinese website!