Message: array_push() expects parameter 1 to be array, null given

$rs = $this->locate_model->like_data('locateName',$str);
		foreach ($rs as $r){
			$ar = array(
				'idLocate' 			=> $r['idLocate'],
				'locatePro' 		=> $r['locatePro'],
				'locateCoun' 		=> $r['locateCoun'],
				'locateSubCoun' 	=> $r['locateSubCoun'],
				'locateName'	 	=> $r['locateName'],
				'lat' 				=> $r['lat'],
				'lng' 				=> $r['lng'],
				'Member_mUser'		=> $r['Member_mUser'],
				'comment_admin'		=> $r['comment_admin'],
				'locateRate' 		=> get_rate('Locate_idLocate', $r['idLocate'])
			);
			
			array_push($this->data['rs'],$ar);
		}

foreach ($rs as $r){
			$ar = array(
				'idLocate' 			=> $r['idLocate'],
				'locatePro' 		=> $r['locatePro'],
				'locateCoun' 		=> $r['locateCoun'],
				'locateSubCoun' 	=> $r['locateSubCoun'],
				'locateName'	 	=> $r['locateName'],
				'lat' 				=> $r['lat'],
				'lng' 				=> $r['lng'],
				'Member_mUser'		=> $r['Member_mUser'],
				'comment_admin'		=> $r['comment_admin'],
				'locateRate' 		=> get_rate('Locate_idLocate', $r['idLocate'])
			);
			if($this->data['rs'] == array()){ $this->data['rs'] = array($ar);}
			else{ array_push($this->data['rs'],$ar);}
		}