Magento 2 store-view progmatically

you can try below code

<?php

ini_set('display_errors', 1);
error_reporting(E_ALL | E_STRICT);


use MagentoFrameworkAppBootstrap;
require __DIR__ . '/app/bootstrap.php';

$bootstrap = Bootstrap::create(BP, $_SERVER);

$obj = $bootstrap->getObjectManager();

$state = $obj->get('MagentoFrameworkAppState');
$state->setAreaCode('frontend');
$storeManager = $obj->get('MagentoStoreModelStoreManagerInterface');
$websiteFactory = $obj->get('MagentoStoreModelWebsiteFactory');

$groupResourceModel=$obj->get('MagentoStoreModelResourceModelGroup');
$storeFactory=$obj->get('MagentoStoreModelStoreFactory');
$groupFactory=$obj->get('MagentoStoreModelGroupFactory');
$eventManager=$obj->get('MagentoFrameworkEvent');
$storeModel     = $obj->create('MagentoStoreModelStore');

$new_store = $websiteFactory->create();
$new_store->setName("da");
$new_store->setCode("da");

$new_store->save();

if ($new_store->getId()) {
 $group = $groupFactory->create();
            $group->setWebsiteId($new_store->getWebsiteId());
            $group->setName('My Custom Group Name');
            $group->setRootCategoryId(2);
            $group->setDefaultStoreId(3);
            $group->save();
}
   $store = $storeFactory->create();
           $store->load('my_custom_store_code');

           if(!$store->getId()){
            $group = $groupFactory->create();
            $group->load('My Custom Group Name', 'name');
            $store->setCode('my_custom_store_code');
            $store->setName('Mu Custom Store Code');
            $store->setWebsite($new_store);
            $store->setGroupId($group->getId());
            $store->setData('is_active','1');
            $store->save($store);
            // Trigger event to insert some data to the sales_sequence_meta table (fix bug place order in checkout)
             $obj->get('MagentoStoreModelStoreManager')->reinitStores();
                  $store->$eventManager->dispatch($eventName, ['store' => $storeModel]);
        }     

According to: php v.7.* and magento 2.1.3. IMO/tested:

<?php

// 1. cd /path/to/magento2root/
// 2. create file: create_stores.php
// check predifined data:
// $postData['store']['group_id']     = 2; // store tab
// $postData['store']['website_id']   = 2; // web site tab
// etc ...
// 3. execute: php create_stores.php
// 4. bin/magento cache:flush
// Rignt way: add current code to 'execute()' method of your command line extension

ini_set('display_errors', 1);
error_reporting(E_ALL | E_STRICT);


use MagentoFrameworkAppBootstrap;
require __DIR__ . '/app/bootstrap.php';

$bootstrap = Bootstrap::create(BP, $_SERVER);

$objectManager  = $bootstrap->getObjectManager();
$appState       = $objectManager->get('MagentoFrameworkAppState');
// echo MagentoFrameworkAppArea::AREA_ADMIN;
// echo MagentoFrameworkAppArea::AREA_ADMINHTML;
$appState->setAreaCode(MagentoFrameworkAppArea::AREA_ADMINHTML);
$sessionManager = $objectManager->create('MagentoFrameworkSessionSessionManagerInterface');
$sessionManager->start();


$storeModel     = $objectManager->create('MagentoStoreModelStore');
$eventManager   = $objectManager->create('MagentoFrameworkEventManagerInterface');
$messageManager = $objectManager->create('MagentoFrameworkMessageManagerInterface');
$filterManager  = $objectManager->create('MagentoFrameworkFilterFilterManager');

$postData['store']['name']         = 'ru_RU';
$postData['store']['code']         = 'ru_ru';
$postData['store']['store_id']     = '';
$postData['store']['group_id']     = 2;
$postData['store']['website_id']   = 2;
$postData['store']['is_active']    = 1;
$postData['store']['sort_order']   = '';
$postData['store']['is_default']   = '';
$postData['store']['store_type']   = 'store';
$postData['store']['store_action'] = 'add';

foreach ($postData['store'] as $key => $value) {
    $postData['store'][$key] = $filterManager->removeTags($value);
}

$eventName = 'store_edit';
/** @var MagentoStoreModelStore $storeModel */
if ($postData['store']['store_id']) {
    $storeModel->load($postData['store']['store_id']);
}

$storeModel->setData($postData['store']);
if ($postData['store']['store_id'] == '') {
    $storeModel->setId(null);
    $eventName = 'store_add';
}

$groupModel = $objectManager->create(
    'MagentoStoreModelGroup'
)->load(
    $postData['store']['group_id']
    // $storeModel->getGroupId()
);

$storeModel->setWebsiteId($postData['store']['website_id']);

if (!$storeModel->isActive() && $storeModel->isDefault()) {
    throw new MagentoFrameworkExceptionLocalizedException(
        __('The default store cannot be disabled')
    );
}

$storeModel->save();
$objectManager->get('MagentoStoreModelStoreManager')->reinitStores();
$eventManager->dispatch($eventName, ['store' => $storeModel]);

in test.php file in magento root:

<?php 

ini_set('display_errors', 1); 
error_reporting(E_ALL | E_STRICT); 


use MagentoFrameworkAppBootstrap;
require __DIR__ . '/app/bootstrap.php';

$bootstrap = Bootstrap::create(BP, $_SERVER);

$obj = $bootstrap->getObjectManager();

$state = $obj->get('MagentoFrameworkAppState');
$state->setAreaCode('frontend');
$storeManager = $obj->get('MagentoStoreModelStoreManagerInterface');
$websiteFactory = $obj->get('MagentoStoreModelWebsiteFactory');
$new_store = $websiteFactory->create();
$new_store->setName("da");
$new_store->setCode("da");
$new_store->save();

this will create a new website "da".

If you want a new store you should use the StoreFactory model and also set the website id, root category etc and then create your loop.