Cardinal number output

[Neel Krishnaswami]

Greg Fortune <gfortune at linuxteams.com> wrote:
> Anyone know of a module or utility function to accept an int and convert
> it to the cardinal number representation?  For example, is there
> anything that will convert ints to a format suitable to printing on a
> check?

Here you are. It's only lightly tested and wholly uncommented and
undocumented, but it ought to get you going in the right direction.

>>> english(-12340)
'negative twelve thousand three hundred forty'

-*-*- 

author = "Neel Krishnaswami <neelk at alum.mit.edu>"
copyright = "This source code is in the public domain."

import string

def english(n):
    pieces = []
    if n < 0:
        pieces.append("negative")
        thousand_powers(-n, 0, pieces)
    else:
        thousand_powers(n, 0, pieces)
    return string.join(pieces, " ")

thousand_words = ["", "thousand", "million", "billion"]
ten_words = ["", "ten", "twenty", "thirty", "forty",
             "fifty", "sixty", "seventy", "eighty", "ninety"]
unit_words = ["zero", "one", "two", "three", "four", "five", "six", "seven",
              "eight", "nine", "ten", "eleven", "twelve", "thirteen",
              "fourteen", "fifteen", "sixteen", "seventeen", "eighteen",
              "nineteen"]

def ten_powers(n, pieces):
    if n < 20:
        pieces.append(unit_words[n])
    else:
        tens, units = divmod(n, 10)
        pieces.append(ten_words[tens])
        if units != 0:
            pieces.append(unit_words[units])
            
def hundred_powers(n, pieces):
    hundreds, units = divmod(n, 100)
    if hundreds == 0:
        ten_powers(units, pieces)
    else:
        ten_powers(hundreds, pieces)
        pieces.append("hundred")
        if units != 0:
            ten_powers(units, pieces)

def thousand_powers(n, thousand_index, pieces):
    millions, mod_millions = divmod(n, 1000000)
    hundreds, units = divmod(mod_millions, 100)
    if hundreds < 100 and hundreds % 10 != 0:
        if millions != 0:
            thousand_powers(millions, thousand_index + 2, pieces)
        hundred_powers(mod_millions, pieces)
        if thousand_index != 0:
            pieces.append(thousand_words[thousand_index])
    else:
        thousands, units = divmod(n, 1000)
        if thousands == 0:
            if thousand_index == 0:
                hundred_powers(units, pieces)
            elif units != 0:
                hundred_powers(units, pieces)
                pieces.append(thousand_words[thousand_index])
        else:
            thousand_powers(thousands, thousand_index + 1, pieces)
            if units != 0:
                hundred_powers(units, pieces)
                if thousand_index != 0:
                    pieces.append(thousand_words[thousand_index])

-*-*-


Neel