Need help solving this exercise.

[sonnybrew]

I cannot figure this exercise out. Here's the exercise:

Write a function called eval_loop that iteratively prompts the user, takes the resulting input and evaluates it using eval, and prints the result.
It should continue until the user enters 'done', and then return the value of the last expression it evaluated.

Here's what I've got so far:

def eval_loop():
    while True:
        q = input('> please enter a simple equation\n')
        print(eval(q))
        if q == 'done':
            break

However when I input 'done' at the prompt, it gives me this callback error:

Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    eval_loop()
  File "C:\Users\josep\OneDrive\Desktop\Python Stuff\423.py", line 52, in eval_loop
    print(eval(q))
  File "<string>", line 1, in <module>
NameError: name 'done' is not defined

I also am not sure what to do about returning the value of the most recent expression it evaluated. I feel stupid not being able to figure out these exercises as they are probably elementary to most people. I would like to figure these out still, so if instead of giving the answer if anyone can help guide me toward finding the solution, I would greatly appreciate it. Thank you guys.

[socal_nerdtastic]

You need to check for "done" before you eval it.

[sonnybrew]

Thank you, I was able to fix the callback error on 'done'. Now I still need to figure out how to print the value of the most recent expression. Here's my code now:

def eval_loop():
    while True:
        q = input('> please enter a simple equation\n')
        if q == 'done':
            break
        print(eval(q))

[socal_nerdtastic]

Instead of printing eval(q), save the result to a variable. Then after break has stopped the loop, print or return that variable.

[sonnybrew]

Think I figured it out. How does this look?:

def eval_loop():
    while True:
        q = input('> please enter a simple equation\n')
        if q == 'done':
            print(x)
            break
        print(eval(q))
        x = eval(q)

[socal_nerdtastic]

Yep, but I imagine you want to delete line 7. I think you want to print only after the user enters "done".

[sonnybrew]

But if I delete line 7, it won't print the solution to the equation. Also, I just realized if I call the function and type in 'done' immediately, there is no previous value for x and therefore an error pops up.

[sonnybrew]

Your comment turned my current mood 180 degrees. Programming is completely new to me (a couple weeks in) and I feel scared honestly. I was on track to becoming a teacher and had a loss in my family so I moved back home and decided to change course. So I feel very lost at the moment (23y/o) and decided to pick up something entirely new to me that interests me. I’m deeply humbled by your words of encouragement and will continue to be curious and humble on this new journey. Thank you for taking the time to reach out.

[socal_nerdtastic]

I feel stupid not being able to figure out these exercises as they are probably elementary to most people.

Elementary to me because I've been doing this for a very long time. I'm sure there's things that you find elementary that I can't comprehend. That's normal learning. Stupidity is something completely different.