prettify number

prettify.py

def prettify(value):
    decimal, integer = math.modf(value)
    decimal = '%0.2f' % decimal
    decimal = decimal[decimal.index('.'):]
    sign = '' if integer >= 0 else '-'
    integer = abs(int(integer))
    result = (',' if integer > 1000 else '') + str(integer % 1000)
    while integer / 1000 > 1:
        integer /= 1000
        result = (',' if integer > 1000 else '') + str(integer % 1000) + result
    return sign + result + (decimal if decimal != '.00' else '')