如果一个元素在多个数组中相同，则随机选择一个数组？

Question

I have 1 multidimensional array:

$adverts = array(array('text'=>'test', 'location' => 'location1'), array('text'=>'test', 'location' => 'location2'), array('text'=>'test', 'location' => 'location1'))

As you can see, two arrays inside that multidimensional array contain the same text for the location element.

How would I detect this, and randomly choose one of them in a foreach loop that looks something like this:

foreach ($adverts as $advert)
        {

            if ($hookName == $advert['advert_location'] && XenForo_Helper_Criteria::userMatchesCriteria($advert['user_criteria']))
            {
                $contents .= $advert['advert_code'];
            }
        }

(I know the arrays don't match)

In that foreach loop, each the location of each array in the multidimensional array is being checked against a predefined value. If more than one of the array's inside the multidimensional array have the same location I want to only use one of them - in other words, contents doesn't get modified for the same location more than once.

However, it should use a random array from each of the matching values.

Is this possible, did you understand it and how would it be done?

Answer 1

Just group them bases on location then select at random each time you loop

$group = array_reduce($adverts, function ($a, $b) {
    $a[$b['location']][] = $b;
    return $a;
});

$contents = array();
foreach($group as $adverts) {
    $contents[] = $adverts[mt_rand(0, count($adverts) - 1)];
}

print_r($contents);

See Example

Answer 2

You can use array_filter to filter out only the elements that match your criteria, then use array rand to select a random one.

 $array = array_filter($array, function($el) use $location{
       return $el["location"] == $location;
 });

 if (count($array) > 1){
     $selected = $array(array_rand($array));
 } elseif (count($array) == 0){
     $selected = $array[0];
 } else {
     $selected = null;
 }

Note this requires php 5.3