PHP7新特性介绍
本文内容根据PHP发布时的 new files 而来,链接地址 : PHP 7 new
特性一览
- Added ?? operator
- Added operato
新的操作符
php// PHP 7之前的写法:比较两个数的大小function order_func($a, $b) { return ($a < $b) ? -1 : (($a > $b) ? 1 : 0);}// PHP新增的操作符 <=>,perfectfunction order_func($a, $b) { return $a <=> $b;}
- Added \u{xxxxx} Unicode Codepoint Escape Syntax
可以直接使用这种方式输出unicode字符
phpecho "\u{1F602}"; // outputs (这个是方括号里面的问号,因为是unicode字符,sg博客不支持,发布出来)
Added error_clear_last() function
新增的一个函数,具体功能没有深入研究-
Implemented the RFC Scalar Type Decalarations v0.5. (Anthony)
变量类型声明(int, float, string , bool)
与之相关的一个语法:declare(strict_types=1);
当strict_types 设定为0,PHP会对函数参数和返回值进行严格的类型判断
需要主要的是1 declare(strict_types=1); 必须放在PHP文件的第一行,此行不能包含其他内容
2 declare(strict_types=1); 只会影响文件内部,包含此声明文件的文件不会影响
3 判断一个函数或者方法是强类型判断还是弱类型判断,就看声明函数或者方法的文件,在开始的时候
是否有declare(strict_types=1);,有这一句,就是强类型
语法演示
php//声明函数返回值类型的写法和参数类型function foobar(float $abc): int { return ceil($abc + 1);}
这里声明了方法参数的类型,当调用的时候,如果不是相应的类型,会先尝试进行类型转换,然后把转换后的值传入
- mplemented the RFC Group Use Declarations. (Marcio)
这个没有什么可说的,PHP use引入类更加方便整齐
php// 新语法写法use FooLibrary\Bar\Baz\{ ClassA, ClassB, ClassC, ClassD as Fizbo };// 以前语法的写法use FooLibrary\Bar\Baz\ClassA;use FooLibrary\Bar\Baz\ClassB;use FooLibrary\Bar\Baz\ClassC;use FooLibrary\Bar\Baz\ClassD as Fizbo;
Implemented the RFC Continue Output Buffering. (Mike)
//TODOImplemented the RFC Constructor behaviour of internal classes. (Dan, Dmitry)
//TODOImplemented the RFC Fix "foreach" behavior. (Dmitry)
foreach 语法的一些边界添加处理,
https://wiki.php.net/rfc/php7_foreachImplemented the RFC Generator Delegation. (Bob)
增强了Generator的功能,这个可以实现很多先进的特性
php<?php//牛逼的用法,轻量级的线程 function g() { yield 1; yield from [2, 3, 4]; yield 5;}$g = g();foreach ($g as $yielded) { var_dump($yielded);}/*int(1)int(2)int(3)int(4)int(5)*/
Implemented the RFC Anonymous Class Support. (Joe, Nikita, Dmitry)
匿名类,这个就不具体介绍了Implemented the RFC Context Sensitive Lexer. (Marcio Almada)
这个特性主要是PHP的面向对象特性更加友好
在class里面类属性或者方法可以使用一些关键字比如 foreach,list,for等
sorry,今天有点发烧,写不下去,以后有空继续

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