Django float format and intcomma optimization

gistfile1.py

import cProfile
from django.template.defaultfilters import floatformat as floatformat_django
from django.contrib.humanize.templatetags.humanize import intcomma as intcomma_django


num = 100000
float_num = 1 / 3.0


def floatformat(value, places=2):
    """Display only desired number of deciaml places. Returns string."""
    left, right = str(value).split('.')
    return '.'.join((left, right[:places]))


def intcomma(value):
    """Add comma on every 10^3. Returns string."""
    value = str(value)

    dot_position = value.find('.')

    if dot_position != -1:
	int_part, decimal_part = value[:dot_position], value[dot_position:]
    else:
        int_part, decimal_part = value, ''

    comma_position = int_part.find(',')

    if comma_position != -1:
	left, right = int_part[:comma_position], int_part[comma_position:]
    else:
        left, right = int_part, ''

    if len(left) > 3:
        comma_ready = ''.join((intcomma(left[:-3]), ',', left[-3:], right))
        if decimal_part:
            return ''.join((comma_ready, decimal_part))
        else:
            return comma_ready
    return value


#===================
# PROFILING RESULTS
#===================
# >>> cProfile.run('for i in xrange(4000): intcomma_django(num)')
# 124002 function calls (120002 primitive calls) in 0.209 seconds
# ^^^^^^                                            ^^^^^
#
# >>> cProfile.run('for i in xrange(4000): intcomma(num)')
# 36002 function calls (32002 primitive calls) in 0.031 seconds
#
# >>> cProfile.run('for i in xrange(4000): floatformat_django(float_num, 3)')
# 1076002 function calls (1064002 primitive calls) in 1.446 seconds
# ^^^^^^^                                             ^^^^^ !!!
#
# >>> cProfile.run('for i in xrange(4000): floatformat(float_num, 3)')
# 12002 function calls in 0.022 seconds