from django.conf import settings

def format(number, decimal_sep, decimal_pos, grouping=0, thousand_sep=''):

    """

    Gets a number (as a number or string), and returns it as a string,

    using formats definied as arguments:

    * decimal_sep: Decimal separator symbol (for example ".")

    * decimal_pos: Number of decimal positions

    * grouping: Number of digits in every group limited by thousand separator

    * thousand_sep: Thousand separator symbol (for example ",")

    """

    # sign

    if float(number) < 0:

        sign = '-'

    else:

        sign = ''

    # decimal part

    str_number = unicode(number)

    if str_number[0] == '-':

        str_number = str_number[1:]

    if '.' in str_number:

        int_part, dec_part = str_number.split('.')

        if decimal_pos:

            dec_part = dec_part[:decimal_pos]

    else:

        int_part, dec_part = str_number, ''

    if decimal_pos:

        dec_part = dec_part + ('0' * (decimal_pos - len(dec_part)))

    if dec_part: dec_part = decimal_sep + dec_part

    # grouping

    if settings.USE_L10N and settings.USE_THOUSAND_SEPARATOR and grouping:

        int_part_gd = ''

        for cnt, digit in enumerate(int_part[::-1]):

            if cnt and not cnt % grouping:

                int_part_gd += thousand_sep

            int_part_gd += digit

        int_part = int_part_gd[::-1]

    return sign + int_part + dec_part