A useful, but painful, one-liner to edit money amounts

[John Posner]

On 8/5/2010 12:36 PM, MRAB wrote:

> You don't need to reverse the string:
>
> def thous_format(integer_string):
>    """
>    add comma thousands separator(s) to an integer-valued string
>    """
>    return re.sub(r"(?<=\d)(?=(?:\d\d\d)+$)", ",", integer_string)

Nice! My first encounter with a look-behind! It appears that a slight 
simplification is possible:

      return re.sub(r"(?<=\d)(?=(\d\d\d)+$)", ",", integer_string)

There no harm in putting \d\d\d into a group, though the group is never 
used.

-John