php array add groups to selection and remove groups

php_array.php

<?php

public function addGroupToSelection($groups) {
        if (count($groups) > 0)
            foreach ($groups as $group)
                foreach ($group as $item)
                    if (!$this->isInGroup($item, $this->main_selection))
                        $this->main_selection[] = $item;
    }
    
public function removeGroupFromSelection($groups) {
        if (count($groups) > 0)
            foreach ($groups as $group)
                    $arr = array_diff($this->main_selection, $group);                
        $this->main_selection = $arr;        
    }

protected function isInGroup($id, $group) {
        if (in_array($id, $group))
            return $this->is_in_group = true;
    }