magento 2 load by attribute method

Question

Load product by attribute i have using the following code

$attribute ='test1'; 
$objectManager =\Magento\Framework\App\ObjectManager::getInstance(); 
$product =$objectManager->get('Magento\Catalog\Model\Product'); 
$product = $product->loadByAttribute('attributename',$attribute]);

but i have the format of values in attribute name field like

test1|test2|test3

then how do i check this loadByAttribute() method

<?php
namespace Vendor\Module\Controller\Adminhtml\EditComments;

use Magento\Framework\App\Action\Action;
use Magento\Backend\App\Action\Context;
use Vendor\Module\Model\ResourceModel\Post\CollectionFactory;
use Magento\Framework\Controller\ResultFactory; 


class SaveEdit extends \Magento\Backend\App\Action
{
    const URL_PATH_EDIT = 'catalog/product/edit';
    protected $_modelFactory;
    protected $urlBuilder;


    public function __construct(
        Context $context,
        \Magento\Framework\UrlInterface $urlBuilder,
        CollectionFactory $modelFactory
    ) {

         parent::__construct($context);
        $this->_modelFactory = $modelFactory;
        $this->urlBuilder = $urlBuilder;
    }

    public function execute()
    {
        $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
        $data  = $this->getRequest()->getParam('custom_table');
        $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
         $product = $objectManager->get('Magento\Catalog\Model\Product');
       $product = $product->loadByAttribute('customattribute',$data['customattribute']);
        // echo $data['customattribute'];
        // echo "<pre>";
        // print_r(get_class_methods($product)); 
        //die;
        $productId = $product->getId();
        if (isset($data['customattribute'])) {
            $collections = $this->_modelFactory->create();
            foreach ($collections as $model) {
            $model = $model->load($data['customattribute']);
            $model->setData('customattribute', $data['customattribute']);
            $model->setData('comments', $data['comments']);
            $model->save();
            }

        }
        $this->messageManager->addSuccess(__('comments has been updated.'));
        if ($productId) {
            $resultRedirect->setPath(
                'catalog/product/edit',
                   ['id' =>  $productId]

            );
        }
        //$resultRedirect->setUrl($this->_redirect->getRefererUrl());
        return $resultRedirect;
    }
}