pmpro-add-countries-dropdown-to-memberslist.php

 <?php
/**
 * This recipe adds a dropdown to the Members List page to filter by country.
 *
 * This requires and extends the recipe to add a sortable column to the member list.
 * @link https://gist.github.com/JarrydLong/7b64606c9cedddd4b7d52d896d2f1e41
 *
 * 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_add_countries_dropdown_to_memberslist() {
	// Let's only do this if required customization recipe is loaded
	if ( ! function_exists( 'mypmpro_sortable_country_col' ) ) {
		return;
	}

	// base url
	$base_url = admin_url( 'admin.php' ) . '?page=pmpro-memberslist&orderby=Country&order=asc';

	// country 2 letter codes
	$countries = array(
		'us' => 'United States',
		'ca' => 'Canada',
		'gb' => 'United Kingdom',
		'au' => 'Australia',
		'de' => 'Germany',
		'cz' => 'Czech Republic',
		'po' => 'Poland',
	);

	$only = false;

	if ( ! empty( $_REQUEST['only'] ) ) {
		$only = sanitize_text_field( $_REQUEST['only'] );
	}

	?>
	<select id="pmpro-memberslist-country-dropdown">
		<option value="">All Countries</option>
		<?php foreach ( $countries as $code => $country ) { ?>
			<option value="<?php echo esc_attr( $code ); ?>" <?php if ( $only == $code ) { ?>selected="selected"<?php } ?>><?php echo esc_html( $country ); ?></option>
		<?php } ?>
	</select>

	<script>
		jQuery(document).ready(function($) {
			$('#pmpro-memberslist-country-dropdown').change(function() {
				window.location.href = '<?php echo $base_url; ?>&only=' + this.value;
			});
		});
	</script>
	<?php

}
add_action( 'pmpro_memberslist_before_table', 'my_pmpro_add_countries_dropdown_to_memberslist' );