Magento2 Attributes – How to Update Attribute Option Programmatically

Please use the following code to get the value from label

$attribute_f = Mage::getModel('eav/config')->getAttribute('catalog_product', 'atr_name');
foreach ( $attribute_f->getSource()->getAllOptions(true, true) as $opt_menuf)
{
    $f_attribute[$opt_menuf['value']] = $opt_menuf['label'];
}

use Magento\Eav\Setup\EavSetupFactory;
use Magento\Store\Model\StoreManagerInterface;

declare:

protected $_eavSetupFactory;

constructor :

public function __construct(
    \Magento\Eav\Setup\EavSetupFactory $eavSetupFactory,
    \Magento\Store\Model\StoreManagerInterface $storeManager,
    \Magento\Catalog\Model\ResourceModel\Eav\Attribute $attributeFactory,
    \Magento\Framework\ObjectManagerInterface $objectmanager,
    ModuleDataSetupInterface $setup,
    \Magento\Catalog\Model\ProductFactory $productloader
) {
    $this->_eavSetupFactory = $eavSetupFactory;
    $this->_storeManager = $storeManager;
    $this->_attributeFactory = $attributeFactory;
    $this->_objectManager = $objectmanager;
    $this->setup = $setup;
    $this->_productloader = $productloader;
}

execute methode :

public function execute(EventObserver $observer)
{
    /** @var $brand \Ktpl\Brand\Model\Brand */
    $brand = $observer->getEvent()->getBrand();
    $option_id = "";

    $data = [];
    $attribute_arr = [$brand['brand_id'] => $brand['brand_title']];
    $optionTable = $this->setup->getTable('eav_attribute_option');
    $attributeInfo=$this->_attributeFactory->getCollection()
           ->addFieldToFilter('attribute_code',['eq'=>"shop_by_brand"])
           ->getFirstItem();

    $attribute_id = $attributeInfo->getAttributeId();

    $eavAttribute = $this->_objectManager->create('Magento\Eav\Model\Config');

    $option=array();
    $option['attribute_id'] = $attributeInfo->getAttributeId();
    $option['value'] = array(0=>array()); // 0 means "new option_id", other values like "14" means "update option_id=14" - this array index is casted to integer

    $storeManager = $this->_objectManager->get('Magento\Store\Model\StoreManagerInterface');
    $stores = $storeManager->getStores();
    $storeArray[0] = "All Store Views";       

    foreach ($stores  as $store) {
        $storeArray[$store->getId()] = $store->getName();
    }


    if (empty($brand['optionId'])) {
        foreach($attribute_arr as $key => $value){
            $option['value'][0][0]=$value;
                foreach($storeArray as $storeKey => $store){
                    $option['value'][0][$storeKey] = $value;
                }                
        }
    }
    else
    {
        foreach($attribute_arr as $key => $value){
                foreach($storeArray as $storeKey => $store){
                    $option['value'][$brand['optionId']][$storeKey] = $value;
                }                
        }
    }

    $eavSetup = $this->_eavSetupFactory->create();
    $eavSetup->addAttributeOption($option)

}