number_to_words() with symbols

[PipWasHere]

If the functionality of number_to_words() is expected to expand, I suggest including some awareness of symbols, especially with those symbols most commonly used with numbers, such as '$', '%', 'º', '/', ':', and the quotes.

Positive/Negative value fixes

Negative values should have a way to alter the prefix and/or add a suffix:
>>> number_to_words(-33)
'minus thirty-three'
>>> number_to_words("-33")
'minus thirty-three'
Optional returns could include 'negative thirty-three', 'thirty-three down'

Similarly, for the leading 'plus':
>>> number_to_words("+33")
'plus thirty-three'
Optional returns could include 'positive thirty-three', 'thirty-three up', or nothing.

Common symbol translations other than 'plus' or 'minus'

Values with unit symbols simply lose them:
>>> number_to_words("33%")
'thirty-three' ... 'percent' suffix lost
>>> number_to_words("$33")
'thirty-three' ... 'dollars' qualifier lost
number_to_words("33º")
'thirty-three' ... 'degrees' suffix lost
>>> number_to_words("33#")
'thirty-three' ... 'pounds' suffix lost
>>> number_to_words("#33")
'thirty-three' ... 'number' or 'hashtag' prefix lost
>>> number_to_words("+/-33")
'plus thirty-three' ... 'or minus' portion of prefix lost
>>> number_to_words("33'")
'thirty-three' ... 'feet' or 'minutes' suffix lost
>>> number_to_words("33""")
'thirty-three' ... 'inches' or 'seconds' suffix lost

Although, not as critical since they are separate numbers, these situations can also arise:
>>> number_to_words("3:2")
'thirty-two' ... 'to', possible 'ratio' or 'odds' suffix, and individuality of numbers are lost
>>> number_to_words("3 + 2")
'thirty-two' ... 'plus' and individuality of numbers are lost
>>> number_to_words("33º22'11""", andword="") (no 'and' to get proper EN_US version)
'three hundred thirty-two thousand, two hundred eleven'
... 'degrees', 'minutes', 'seconds' as well as individuality of numbers are lost

I understand why it ignores spaces and commas, but other than '+', '-', and '.', it treats all symbols as meaningless, which they are not, and does not handle repetitious or multiple symbols, such as used in dates:

>>> number_to_words("22.11.33")
'twenty-two point one one three three' ... second '.' is ignored
>>> number_to_words("11/22/2033")
'eleven million, two hundred and twenty-two thousand and thirty-three' ... slashes are ignored
Dates themselves, of course, are a whole other area of complication, but the symbols are still being lost.

Other usages lost

>>> number_to_words("2a12")
'two hundred and twelve' ... hex digits are lost
>>> number_to_words("0010.0011.0100.0111")
'ten point zero zero one one zero one zero zero zero one one one' ... leading zeros and other 'dots' are lost
>>> number_to_words("2/3")
'twenty-three' ... 'two thirds' is misinterpreted or could have been a mathematical division
>>> number_to_words("1-1/2")
'one hundred and twelve' ... whole and fractional values misinterpreted
'>>> number_to_words("4!")
'four' ... 'factorial' suffix lost

Final thoughts

The symbols that might benefit best from this library are those with pluralized written forms: dollars, feet, inches, degrees, seconds, minutes, pounds, etc., where the numeric value would be significant, e.g., "33º", '12"', "1¢", "$1", and so on.

The translation that might be most useful would be the option to translate fractional values or ratios, e.g. "2/3", "1-1/2", "3:2", "1000:1", etc.

Translating mathematical symbolism could open up another whole toolbox.