There's got to be a better way to do this:
def editmoney(n) :
return((",".join(reduce(lambda lst, item : (lst + [item]) if
item else lst,
re.split(r'(\d\d\d)',str(n)[::-1]),[])))[::-1])
>>> editmoney(0)
'0'
>>> editmoney(13535)
'13,535'
>>> editmoney(-14535)
'-14,535'
>>> editmoney(123456)
'123,456'
>>> editmoney(1234567890)
'1,234,567,890'
>>> editmoney(-1234)
'-1,234'
The basic idea here is that we want to split the string of digits
into groups of 3 digits, aligned at the right. Because regular
expressions are right to left, we have to reverse the string to
do that, then reverse again at the end. s[::-1} reverses an
interable.
"split" with a capturing group introduces empty strings into the
list. Hence the "reduce" and lambda to get rid of them.
Any better ideas?
(Yes, I know there's a built-in feature for this scheduled for
Python 2.7.)
John Nagle
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