使用PHP搜索数组中的值

Question

I have a list of users in my mongodb database, which can then follow each other -pretty standard. Using php I want to check if a specific user is following another user. My data looks like this.

array (
  '_id' => ObjectId("56759157e1095db549d63af1"),
  'username' => 'Joe',
  'following' => 
  array (
    0 => 
    array (
      'username' => 'John',
    ),
    1 => 
    array (
      'username' => 'Tom',
    ),
  ),
)
array (
      '_id' => ObjectId("56759132e1095de042d63af4"),
      'username' => 'Tom',
      'following' => 
      array (
        0 => 
        array (
          'username' => 'Joe',
        ),
        1 => 
        array (
          'username' => 'John',
        ),
        2 => 
        array (
          'username' => 'Sam',
        ),
      ),
    )

I want a query that will check if Joe is following Sam (which he's not) - so it would produce no results. However, if I was to query the database to check if Tom was following Sam, then it would produce a result to indicate he is (because he is). Do you know how I would do this in PHP? I've experimented with Foreach loops, but I haven't been able to get the results I want.

Answer 1

Make it by DB query, by php it will take more resources
Still if you want by php you can make it so

$following=false;
foreach($data as $v) if ($v['username'] == 'Joe') {
    foreach($v['following'] as $v1) if (in_array('Sam', $v1)) {
        $following=true;
        break 2;
    }
}
echo $following;