php – array_map内联匿名函数

它的工作,但是当我尝试与user_meta相同它不工作..

$user_meta = Array ( [interest] => Array ( [0] => Array ) [type] => 
     Array ( [0] => Array ) [user_status] => Array ( [0] => deny)
     [firstname] => Array ( [0] => ) [lastname] => Array ( [0] => B ) 
     [email] => email@cc.com ) 

     $user_meta = array_map(function($a) { return $a[0]; },$user_meta);

“解析错误：语法错误,意外的T_FUNCTION,expecting’)’在”

here is the test link showing error