「代码」

<?php
$before = [
    'user1' => 15,
    'user2' => 3,
    'user3' => 20,
    'user4' => 8,
    'user5' => 5
];
$result = check_array($before,function($v){
  return $v % 3 === 0; 
});

function check_array($before,$callback){
    $after = [];
    foreach ($before as $key => $v){
        if($callback($v)){
            $after[$key] = $v;
        }
    }
    return $after;
}
var_dump($result);

结果 (jié guǒ)

array(2) {
  ["user1"]=>
  int(15)
  ["user2"]=>
  int(3)
}