Get Store ID by store code Magento 2

You could use Magento\Store\Api\StoreRepositoryInterface.

In your constructor:

protected $storeRepository;

public function __construct(
    \Magento\Store\Api\StoreRepositoryInterface $storeRepository
) {
    $this->storeRepository= $storeRepository;
}

From where you would like to get the store ID:

try {
    $store = $this->storeRepository->get('store_code');
    echo $store->getId(); // this is the store ID
} catch (\Magento\Framework\Exception\NoSuchEntityException $e) {
    // store not found
}

Please use below code :

$objectManager =  \Magento\Framework\App\ObjectManager::getInstance();    
$storeManager = $objectManager->create("\Magento\Store\Model\StoreManagerInterface");
$storecode = 'de'; //storecode here
    // get array of stores with storecode as key
    $stores = $storeManager->getStores(true, true);
    // check stores array for this storecode 
    if(isset($stores[$storecode]){
        $store_id = $stores[$storecode]->getId();
    }
echo $store_id;