Complex translation strings in WordPress themes and plugins

wp-translation-strings.php

<?php
/**
 * The following is the proper way to handle complex translation strings.
 * By Justin Tadlock
 * @see https://wpchat.com/t/do-you-use-format-placeholders-s-and-d-in-translatable-strings/1138/11
 */
$number = get_donation_count();

$string = sprintf(
	// translators: %s is the number of donations.
	_n( 'You have %s donation.', 'You have %s donations', $number, 'my-domain' ),
	"<span>{$number}</span>"
);