What's the best way to format a phone number i

问题:

If all I have is a string of 10 or more digits, how can I format this as a phone number?

Some trivial examples:

555-5555
555-555-5555
1-800-555-5555

I know those aren't the only ways to format them, and it's very likely I'll leave things out if I do it myself. Is there a python library or a standard way of formatting phone numbers?

回答1:

for library: phonenumbers (pypi, source)

Python version of Google's common library for parsing, formatting, storing and validating international phone numbers.

The readme is insufficient, but I found the code well documented.

回答2:

Seems like your examples formatted with three digits groups except last, you can write a simple function, uses thousand seperator and adds last digit:

>>> def phone_format(n):                                                                                                                                  
...     return format(int(n[:-1]), ",").replace(",", "-") + n[-1]                                                                                                           
... 
>>> phone_format("5555555")
'555-5555'
>>> phone_format("5555555")
'555-5555'
>>> phone_format("5555555555")
'555-555-5555'
>>> phone_format("18005555555")
'1-800-555-5555'

回答3:

Here's one adapted from utdemir's solution and this solution that will work with Python 2.6, as the "," formatter is new in Python 2.7.

def phone_format(phone_number):
    clean_phone_number = re.sub('[^0-9]+', '', phone_number)
    formatted_phone_number = re.sub("(\d)(?=(\d{3})+(?!\d))", r"\1-", "%d" % int(clean_phone_number[:-1])) + clean_phone_number[-1]
    return formatted_phone_number

回答4:

A simple solution might be to start at the back and insert the hyphen after four numbers, then do groups of three until the beginning of the string is reached. I am not aware of a built in function or anything like that.

You might find this helpful: http://www.diveintopython3.net/regular-expressions.html#phonenumbers

Regular expressions will be useful if you are accepting user input of phone numbers. I would not use the exact approach followed at the above link. Something simpler, like just stripping out digits, is probably easier and just as good.

Also, inserting commas into numbers is an analogous problem that has been solved efficiently elsewhere and could be adapted to this problem.