问题
Telephone number should be international and user has to enter the complete phone number with country code.
For that I need a regex for formatting the phone number.
回答1:
For real regex testing use RegexKitLite.
As for the regular expression itself, something like this (from Validate Phone Numbers: A Detailed Guide) should work:
^\+(?:[0-9] ?){6,14}[0-9]$
Note that when you specify it in your code you need to escape the backslash character (\), so it would look like this:
NSString *regexString = @"^\\+(?:[0-9] ?){6,14}[0-9]$";
来源：https://stackoverflow.com/questions/4301363/telephone-number-format-should-be-international-is-there-any-regex-for-phone-num