iterating in reverse

[Laura Creighton]

> I just encountered a problem that required reverse iterating to solve,
> and my current solution, though it works, is not so satisfying:
> 
> def commafy(val):
>     """Return val as string with commas every thousandth place."""
>     val = str(val)
>     ret = ''
>     c = 0
>     for i in range(len(val) - 1, -1, -1):
>         if c and not c % 3:
>             ret = ',' + ret
>         ret = val[i] + ret
>         c += 1
>     return ret
> 
> This is one of the few times I just haven't been able to come up with
> an elegant and -- dare I say it -- aesthetically pleasing solution in
> Python. I suspect the lack is my own, not Python's.
> 
> Nick
> 
> -- 
> # sigmask.py  ||  version 0.2  ||  2003-01-07  ||  Feed this to your Python.
> print reduce(lambda x,y:x+chr(ord(y)-1),'Ojdl!Wbshjti!=obwAqbusjpu/ofu?','')
> 
> -- 
> http://mail.python.org/mailman/listinfo/python-list

Well, you could reverse the string and operate on that, and then reverse 
it back ...

Laura Creighton