iterating in reverse

[Neil Hodgson]

Steve Holden:

> Here's my own non-reversing solution. Again, it would need tweaking for
> negative numbers to avoid results like "-,123".
>
>     def commafy(val):
> ...

   Well we may as well try a one liner (almost):

def commafy(val):
 u = str(val)
 return ''.join([u[i]+(['',',',''][(len(u)-i)%3]) for i in
range(len(u))])[:-1]

for i in [1, 12, 123, 1234, 12345, 123456, 1234567, 12345678]:
 print i, ":", commafy(i)

   Mmm, Perl envy ...

   Neil