format a number for output

[Yu-Xi Lim]

Yu-Xi Lim wrote:

>  >>> b = 189028499
>  >>> ','.join([str(b)[::-1][x:x+3] for x in range(len(str(b)))[::3]])[::-1]
> 
> '-,189,028,499'

Oops, mis-paste

 >>> b = -189028499
 >>> ','.join([str(b)[::-1][x:x+3] for x in range(len(str(b)))[::3]])[::-1]