Python elegant inverse function of int(string,base)

python

Solution

This thread has some example implementations.

Actually I think your solution looks rather nice, it's even recursive which is somehow pleasing here.

I'd still simplify it to remove the `else`, but that's probably a personal style thing. I think `if foo: return` is very clear, and doesn't need an `else` after it to make it clear it's a separate branch.

def digit_to_char(digit):
    if digit < 10:
        return str(digit)
    return chr(ord('a') + digit - 10)

def str_base(number,base):
    if number < 0:
        return '-' + str_base(-number, base)
    (d, m) = divmod(number, base)
    if d > 0:
        return str_base(d, base) + digit_to_char(m)
    return digit_to_char(m)

I simplified the 0-9 case in `digit_to_char()`, I think `str()` is clearer than the `chr(ord())` construct. To maximize the symmetry with the `>= 10` case an `ord()` could be factored out, but I didn't bother since it would add a line and brevity felt better. :)

Problem

Python allows conversions from string to integer using any base in the range [2,36] using: ``` int(string,base) ``` I am looking for an elegant inverse function that takes an integer and a base and returns a string. For example: ``` >>> str_base(224,15) 'ee' ``` I came up with the following solution: ``` def digit_to_char(digit): if digit < 10: return chr(ord('0') + digit) else: return chr(ord('a') + digit - 10) def str_base(number,base): if number < 0: return '-' + str_base(-number,base) else: (d,m) = divmod(number,base) if d: return str_base(d,base) + digit_to_char(m) else: return digit_to_char(m) ``` Note: `digit_to_char()` works for bases <= 169 arbitrarily using ASCII characters after `z` as digits for bases above 36. Is there a Python built‑in, library function, or a more elegant inverse function of `int(string,base)`?

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