php语法怎么实现二维数组去重

function unique_array($array) {
  $temp = array();
  foreach ($array as $key => $value) {
    $temp[$key] = implode(',', $value);
  }
  $temp = array_unique($temp);
  $result = array();
  foreach ($temp as $key => $value) {
    $result[$key] = explode(',', $value);
  }
  return $result;
}
 
$students = array(
  array('id' => 1, 'name' => '张三', 'age' => 18),
  array('id' => 2, 'name' => '李四', 'age' => 19),
  array('id' => 3, 'name' => '王五', 'age' => 20),
  array('id' => 4, 'name' => '张三', 'age' => 18)
);
 
$result = unique_array($students);
print_r($result);