Binary/decimal/hex converter using Tkinter

I debated long and hard before posting this question, and I did a lot of experimenting. I just can't seem to work out an 'elegant', concise way to get done what I want done in the manner I want it done. I found it very hard to research because of the difficulty in not knowing exactly what to search for.

Again, I am writing a converter for binary, decimal and hex using Tkinter and not using any of Python's built-in math functions.

In the code I have one class, within it many methods. I have the methods to convert from binary to decimal and hex working correctly (bin_to_dec & bin_to_hex, respectively). I am now working on the 'from decimal' conversions. I have the dec_to_bin method working correctly, as well. My issue is with the dec_to_hex method. I want it to use the dec_to_bin method to convert the string to binary first and then use the bin_to_hex method for the final conversion. In doing this it has to overlook the lines of code that tell the 2 methods to display their results; but rather to store the results and transport them to the dec_to_hex method.

I'm going to post the entire code except for the method that creates the Tkinter widgets:

```
def base_check(self):
""" Disable Checkbox that's connected with chosen Radiobutton. """
sel_radio = self.base.get()

for radio, cb in self.cb_to_radio.items():
if radio == sel_radio:
cb.configure(state = DISABLED)
else:
cb.configure(state = NORMAL)

def conv_segue(self):
""" Decides and directs towards proper conversion method.
Reading the 'convert from' radiobuttons. """
base = self.base.get()

if base == 'bin':
bits = self.input_str.get()

# test string validity
bit_list = list(bits)
ill_bits = ['2', '3', '4', '5', '6', '7', '8', '9']
for bit in bit_list:
if bit in ill_bits:
self.output_disp.delete(0.0, END)
self.output_disp.i

Use more python, e.g. instead of:

for i in hex_digits.keys():
    if i == tot:
        tot = hex_digits[i]
    else:
        tot = tot

Remove extraneous keys() and it becomes:

for i in hex_digits:
    if i == tot:
        tot = hex_digits[i]
    else:
        tot = tot

Then remove unnecessary else and it is:

for i in hex_digits:
    if i == tot:
        tot = hex_digits[i]

And finally remove the loop:

tot = hex_digits.get(i, tot)

There I saved you a loop, a branch and 4 out of 5 lines of code.

A few iterations like this over the entire module and you might like your code after all!

StackExchange Code Review Q#8740, answer score: 6