<?php
// PHP 7 之前版本用法
use some
amespaceClassA;
use some
amespaceClassB;
use some
amespaceClassC as C;
use function some
amespacefn_a;
use function some
amespacefn_b;
use function some
amespacefn_c;
use const some
amespaceConstA;
use const some
amespaceConstB;
use const some
amespaceConstC;
// PHP 7+ 用法
use some
amespace{ClassA, ClassB, ClassC as C};
use function some
amespace{fn_a, fn_b, fn_c};
use const some
amespace{ConstA, ConstB, ConstC};
?>2.序列号函数unserialize的新增了过滤功能
// 转换对象为 __PHP_Incomplete_Class 对象
$data = unserialize($foo, ["allowed_classes" => false]);
// 转换对象为 __PHP_Incomplete_Class 对象，除了 MyClass 和 MyClass2
$data = unserialize($foo, ["allowed_classes" => ["MyClass", "MyClass2"]);
// 默认接受所有类
$data = unserialize($foo, ["allowed_classes" => true]);
3.通过define定义常量数组
<?php
define('ANIMALS', [
'dog',
'cat',
'bird'
]);
echo ANIMALS[1]; // 输出 "cat"
define("GREETING","Hello you! How are you today?",TRUE);
echo constant("greeting"); //返回常量的值
?>4.三目运算符null合并
<?php
// 如果 $_GET['user'] 不存在返回 'nobody'，否则返回 $_GET[&#
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