PHP Array_intersect on multidimensional array with unknown number of keys

Question

I'm trying to make advanced search filters in an application that holds resources (people). I've got all the results in 1 multidimensional array. A user of the application can search for the persons Job title, skills, work field and country.

I've already made the part where I look up the people that meet the criteria given by the user. These results are stored in a multidimensional array. If the user is looking for someone with a specific resource with a job title and a specific skill the return value is this:

$realfilters = array(2) {
["resourcesWithJobtitle"]=> array(6) {
   [0]=> string(1) "1"
   [1]=> string(2) "48"
   [2]=> string(2) "88"
}
["resourcesWithSkill"]=> array(9) {
   [0]=> string(1) "4"
   [1]=> string(1) "8"
   [2]=> string(1) "48"
   [3]=> string(2) "50"
}

When the user also looks for a work field this is added to the result:

["resourcesWithWorkfield"]=> array(3) {
   [0]=> string(2) "48"
   [1]=> string(2) "96"
   [2]=> string(2) "97"
}

I need to know which resources meet all dimensions of the array so I can display them. (So in this example I need an array with just 1 value: 48). I think I need to use array_intersect but can't seem to get it right.

Answer 1

One of the possible solutions: you may first extract() the $realfilters array values to variables, and then apply the array_intersect() to them. But this solution is applicable only if there are not many possible filters.

Another one and probably the best solution would be to intersect in a loop, something like:

$res_arr = array_shift($realfilters);
foreach($realfilters as $filter){
     $res_arr = array_intersect($res_arr, $filter);
}

Answer 2

$intersection = call_user_func_array('array_intersect', $array);

That will give you the elements present in all the sub arrays of $array.

edit- This above is like a shortcut for writing:

$intersection = array_intersect($array['a'], $array['b'], ...and so on for all elements...);

A loop could be used as well

$intersection = reset($array);
foreach ($array as $subarr) {
    $intersection = array_intersect($intersection, $subarr);
}
print_r($intersection);