php - Laravel validator 'in' issue for numbers in input -

i need in fixing issue in using laravel 'in' validator match given input against multiple comma separated string of values. issue when there number in input , not matches of comma separated values gives exception:

preg_match() expects parameter 2 string, array given 

however should give error message in validator object input field not match. instead gives above mentioned exception. following code:

 if (!empty($program)) {             $institution_id = $program->institutionid;             $roster_users = $program->usersrosters()->where('profiletype', 'student')->get();             if (!empty($roster_users)) {                 $rostered_users_ids = implode(',', $roster_users->lists('id'));             }             if (!empty($roster_users)) {                 $rostered_users_usernames = implode(',', $roster_users->lists('username'));             }             $teacher_roster_users = $program->usersrosters()->where('profiletype', 'external staff')->get();             if (!empty($teacher_roster_users)) {                 $teacher_rostered_users_usernames = implode(',', $teacher_roster_users->lists('username'));             }             if (!empty($teacher_roster_users)) {                 $teacher_rostered_users_data = $teacher_roster_users->lists('id', 'username');             }         }         $rules = [             'aasectionname.required' => '501 – aa section not exist',             'aaid' => 'numeric|exists:users,id|in:' . $rostered_users_ids . '|aaidinstitutionmismatch:' . $institution_id,             'institutionid' => 'numeric|in:' . $institution_id,             'username' => 'exists:users,username|in:' . $rostered_users_usernames . '|usernameinstitutionmismatch:' . $institution_id,             'schoolid' => 'numeric',             'groupowner' => 'in:'.$teacher_rostered_users_usernames,             'remove' => 'in:0,1'         ];         $messages = [             // institutionid             'institutionid.numeric' => '101 – invalid institution id',             'institutionid.in' => '102 – institution id not match program',             // usernames             'username.exists' => '201 – username not exist',             'username.in' => '202 – username not rostered program',             'username.usernameinstitutionmismatch' => '203 – user/institution mismatch - username not assigned institution',             // aaid             'aaid.numeric' => '301 – aa id not exist',             'aaid.exists' => '301 – aa id not exist',             'aaid.in' => '302 – aa id not rostered program',             'aaid.aaidinstitutionmismatch' => '303 – aa id/institution mismatch – aaid not assigned institution',             // mismatch             'bothmismatch' => '401 – aaid/username/schoolid not match (this combination of @ least 2 of these items)',             // teacher             'groupowner.in' => '501 – groupowner not exist',             // remove             'remove' => '601 – no student record match remove',         ];   excel::load($file, function($excel) use($program, $rules, $messages, $errors, &$errors_data, $teacher_rostered_users_data) {             global $totalmismatch;             $results = $excel->get();             $program_group_model = new programgroup;             $option_model = new option;             $group_default_status_id = key($option_model->getprogramsstatus(['active']));             $groupvisibilitystatusid = $group_type = $option_model->getvisibilityoptions('question visibility','private');             $data = [];             $lastsecid = null;             $groupsectionpreviousname = null;             $groupname = null;             $data['status'] = $group_default_status_id;             $data['program_id'] = $program->id;             $groupname_lists = $program_group_model->with(['programs' => function ($query) use ($program){                 $query->where('programid','=',$program->id);             }])->get()->lists('name','id');              foreach ($results $key => $row) {                 $inputs = $row->toarray();                 $groupname = trim($inputs['usergroup']);                 $errors = [];                 // stop reading excel when aasectionname empty                 if (empty($groupname) || $groupname == null) {                     $errors['remove'] = $messages['aasectionname.required'];                 }                 $validator = validator::make($inputs, $rules, $messages);                 if ($validator->fails()) {                     $errors = $validator->messages()->toarray();                     foreach ($errors $error) {                         foreach ($error $e) {                             $errors_data[] = [$key + 2, $e];                         }                     }                 } else {                     $aaid = intval($inputs['aaid']);                     $groupowner_name = $inputs['groupowner'];                     if (!empty($teacher_rostered_users_data[$groupowner_name])) {                         $groupowner_id = $teacher_rostered_users_data[$groupowner_name];                         $data['owner'] = $groupowner_id;                     }                     $remove = intval($inputs['remove']);                     // remove existing student roster                     if (!empty($remove)) {                         $removed = false;                         $user_ids = is_array($aaid) ? $aaid : [$aaid];                         $program_group = $program->programgroups()->where('name', $groupname);                         if (!empty($program_group)) {                             $program_group = $program_group->first();                         }                         if (!empty($program_group)) {                             $program_group = $program_group->users();                         }                         if (!empty($program_group) && !empty($user_ids)) {                             $removed = $program_group->detach($user_ids);                         }                         if (!$removed) {                             $errors['remove'] = $messages['remove'];                         }                     } else {                         if (!in_array($groupname, $groupname_lists) || $groupsectionpreviousname != $groupname)  {                             $data['name'] = $groupname;                             $data['group_id'] = array_search($groupname, $groupname_lists);                             $data['group_type'] = $groupvisibilitystatusid;                             $sectionid = $program_group_model->saveprogramgroup($data);                             $data[$sectionid]['selected'][] = $aaid;                             $groupname_lists[$sectionid] = $groupname;                         } else {                             $temp = array_flip($groupname_lists);                             $data[$temp[$groupname]]['selected'][] = $aaid;                         }                     }                     if ($totalmismatch === 2) {                         $errors['bothmismatch'] = $messages['bothmismatch'];                     }                     foreach ($errors $error) {                         $errors_data[] = [$key + 2, $error];                     }                 }                 $groupsectionpreviousname = $groupname;             }             $programaasectionmodelforsectionusers = new programsectionuser();             $programaasectionmodelforsectionusers->saveprogramgroupusers($data);         }); 

$rules

array:7 [   "aasectionname.required" => "501 – aa section not exist"   "aaid" => "numeric|exists:users,id|in:28,29,32,33,25,24,27|aaidinstitutionmismatch:42"   "institutionid" => "numeric|in:42"   "username" => "exists:users,username|in:kabeer,ayaz,fddesaaweqq,fdawerascvdfc,haseeb,kamran,shahid|usernameinstitutionmismatch:42"   "schoolid" => "numeric"   "groupowner" => "in:externalstaff,rahat,uzma,sahar,haseebahmad,saimariaz,fredrick"   "remove" => "in:0,1" ]