How to break out of multiple loops?

Question

Given the following code (that doesn\'t work):

while True:
    #snip: print out current state
    while True:
        ok = get_input(\"Is this ok? (y/n)\")
          


        

Answer 1

I'd like to remind you that functions in Python can be created right in the middle of the code and can access the surrounding variables transparently for reading and with nonlocal or global declaration for writing.

So you can use a function as a "breakable control structure", defining a place you want to return to:

def is_prime(number):

    foo = bar = number

    def return_here():
        nonlocal foo, bar
        init_bar = bar
        while foo > 0:
            bar = init_bar
            while bar >= foo:
                if foo*bar == number:
                    return
                bar -= 1
            foo -= 1

    return_here()

    if foo == 1:
        print(number, 'is prime')
    else:
        print(number, '=', bar, '*', foo)

---

>>> is_prime(67)
67 is prime
>>> is_prime(117)
117 = 13 * 9
>>> is_prime(16)
16 = 4 * 4