**const 关键字可用来在类外定义常量 5.3** const HI="定义常量另一种方法"; **nowdoc传递一段代码不解析变量,类似heredoc5.3** ~~~ $str = <<<'EOD' 这里可以是代码$qq不解析 EOD; echo $str; ~~~ **命名空间5.3** ~~~ namespace A; class B{ } $c = new \A\B(); ~~~ **短数组5.4** ~~~ $arr = ["key" => "value", "key2" => "value2"]; $arr = [1,2,3,4]; ~~~ **函数返回数组5.4** myfunc()[0]; **实例化访问类成员5.4** (new Foo)->bar(); **json不转换中文5.4** json_encode(array("中文"), JSON_UNESCAPED_UNICODE); **函数中传递引用** ~~~ function goo(&$a) { return $a = 100; } $a = 3; echo goo($a);//输出100 ~~~ always_populate_raw_post_data = -1 5.6报错