Cocoa: Convert number to comma-separated NSString
At some point in your Mac, iPhone, or iPad development you may find the need to express a long number (1000000000) as a comma-separated string (1,000,000,000) to make life easier on your users. The NSNumberFormatter class is a rich tool for converting numbers to strings supporting different types of currencies and localizations. It’s also the perfect class to leverage for our comma-ing task.