insert thousands separators

[gyro]

Nick Vargish wrote:
> Gerhard Häring <gh at ghaering.de> writes:
> 
> 
>>So if you only want to print the fractional value, str() will do
>>fine. But str() won't make floats capable of representing arbitrary
>>numbers, either ;-)
> 
> 
> If I really cared about floats, I could str(fval).split('.') -- after
> checking for floatness, of course. But since I don't care about
> floats, I'm gonna let it ride for now -- until it bites me in some
> other context. :^)
> 
> Nick
> 

Hi,
How about the ugliness below for floating point numbers?

-g


===

def include_separator(val,thous_sep=',',dec_sep='.'):
     """Format a floating point number so that it has thousands 
separators.
 

     """

     import re

     snum = str(val)

     # regular expression for a general floating point number 

     num_regex = re.compile(''' 

       (?P<msign>[-+])?                          # perhaps a leading 
sign
       ((?P<mnum>[0-9]+)(?P<mfrc>\%s?[0-9]*)|    # a number, a 
separator, and a decimal part
       (?P<mdec>\%s[0-9]+))                      # or just a separator 
and decimal part
       (?P<mexp>[eE][-+]?[0-9]+)?                # and perhaps an 
exponent
       ''' % (dec_sep,dec_sep), re.VERBOSE)

     msrch = num_regex.search(snum)

     # find out which pieces of the general floating point number 

     # were found in the target 

     if msrch:
         ms = msrch.group
         msign = ms('msign') or ''
         mnum = ms('mnum') or ''
         mexp = ms('mexp') or ''
         mfrc = ms('mfrc') or ''
         mdec = ms('mdec') or ''

         # put thousands separator in place in the whole number piece 

         if mnum:
             if int(mnum) == 0: mnum = '0'
             cc = []
             rnum = list(mnum)
             rnum.reverse()
             i = 1
             for dig in rnum:
                 cc.append(dig)
                 if i % 3 == 0 and i != len(rnum): cc.append(thous_sep)
                 i += 1
             cc.reverse()
             mnum = ''.join(cc)

     # reassemble the pieces 

     fnum = msign + (mnum + mfrc or mdec) + mexp

     return fnum

if __name__ == "__main__":
     print include_separator('-12345.234') 

     print include_separator('-000000.00234') 

     print include_separator('-0.00234') 

     print include_separator(12345) 

     print include_separator('-12345,234e4','.',',') 

     print include_separator('1.234') 

     print include_separator('-123.234') 

     print include_separator('-123456,234','.',',')