变量运算得到常量名称字符串怎么返回常量对应的值？

Question

变量运算得到常量名称字符串怎么返回常量对应的值？

Answer 1

<?php
define('HELLO', 'world');
define('GOOD', 'boy');$arr = array(
                        array(
                                'constant' => 'HELLO'
                        ),
                        array(
                                'constant' => 'GOOD'
                        )
                );foreach ($arr as $val) {
        echo constant($val['constant']);
}
?>

Answer 2

加个大括号就可以了，谢谢
<?php
$arr=array();
$str="";
define("HELLO","WORLD");
define("GOOD","BOY");
$arr=array(
array('contents'=>HELLO),
array('contents'=>GOOD)
);
foreach($arr as $k=> $v){
$str.="{$v['contents']}_";
}
echo $str;
?>