Show specific Country in Billing address Drowndown

my-pmpro-show-specific-countries.php

<?php
/**
 * This recipe is an example of how to keep only specific countries in the dropdown.
 * and remove all other countries from the "Country" dropdown select.
 *
 * The PMPro default country is "US" (United States), to set
 * your custom default country, please refer to this article.
 * @link https://www.paidmembershipspro.com/change-the-default-country-of-your-membership-website/
 *
 * For available countries and their shortcode see:
 * @link https://github.com/strangerstudios/paid-memberships-pro/blob/master/includes/countries.php
 *
 * NOTE: This recipe is not intended for or compatible with the PMPro State Dropdowns Add On.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_countries_show_only_selected( $countries ) {
    // Define the allowed countries
    $allowed_countries = array(
        'CH', 'RS', 'JP', 'CA', 'US', 'KR', 'AT', 'BE', 'BG', 'HR', 'CY', 'CZ', 'DK', 'EE', 'FI', 'FR', 'DE', 'GR', 'HU', 'IE', 'IT', 'LV', 'LT', 'LU', 'MT', 'NL', 'PL', 'PT', 'RO', 'SK', 'SI', 'ES', 'SE'
    );
    
    // Loop through and remove any country not in the allowed list
    foreach ( $countries as $country_code => $country_name ) {
        if ( ! in_array( $country_code, $allowed_countries, true ) ) {
            unset( $countries[ $country_code ] );
        }
    }
    
    return $countries;
}
add_filter( 'pmpro_countries', 'my_pmpro_countries_show_only_selected' );