[ Python 常見問題 ] How to print number with commas as thousands separators?

Source From Here
Question
I am trying to print an integer in Python 2.6.1 with commas as thousands separators. For example, I want to show the number 1234567 as 1,234,567. How would I go about doing this? I have seen many examples on Google, but I am looking for the simplest practical way.

How-To
The Python standard library locale can help:

The locale module opens access to the POSIX locale database and functionality. The POSIX locale mechanism allows programmers to deal with certain cultural issues in an application, without requiring the programmer to know all the specifics of each country where the software is executed.

One simple example:

>>> import locale
>>> locale.format("%d", 1255000, grouping=True)
'1255000'
>>> locale.setlocale(locale.LC_ALL, 'en_US')
'en_US'
>>> locale.format("%d", 1255000, grouping=True)
'1,255,000'

Sure, you don't need internationalization support, but it's clear, concise, and uses a built-in library. Another way is to use string format(Only works in Python 2.7 and higher.):

>>> '{0:,}'.format(123456) # See format string syntax.
'123,456'