在array_walk PHP中取消设置元素

Question

I use array_walk to walk through an array "sessions", each time, I send my data ($uid) to the function.

$uid = ...;

array_walk($sessions, array($this,'handle_each_session'), array('uid' => $uid));

in the function 'handle_each_session', there is another variable $package . If $package is empty, I will unset the element (remove the element from the array), otherwise I will put the $packag e into the element.

private function handle_each_session (& $s, $k, $data)
{
   $uid = $data['uid'];
   $s['uid'] = $uid;
   $package = $this->get_random_package($uid);

   //- if $package is not defined, then unset the element
   if (!isset($package) || empty($package))
   {
       unset($s);
       return;
   }

   //- otherwise put the package into the element
   $s['package'] = $package;
}

The result is the element $s is still there, is not removed from the sessions array.

How can I archive that?

Answer 1

You can't do it this way. Unset($s) does not destroy the $session var passed by reference. It destroy the link between $s and $session. See documentation here: http://php.net/manual/en/language.references.unset.php

you better pass the whole $session by reference to a new "handle_session" function and go through the $session array in it. using unset($session[$key]) should work.

Answer 2

Thanks @Bar-code to let me know, I cannot unset the element that way.

I use the array_filter to remove all elements with an empty package as follow:

private function is_not_null_package($session)
{
        $package = $session['package'];
        $empty = (!isset($package) || empty($package));
        return (!$empty);
}

//- handle sessions
array_walk($sessions, array($this,'handle_each_session'), array('uId' => $uid));

//- filter sessions
//- remove all sessions with empty packages
$sessions = array_filter($sessions, array($this, 'is_not_null_package') );

It works for me.