Python while loop won't end

Question

So I have a code that project the user's bill. I put it on a loop so that it keeps repeating itself until the user don't want to continue.

here is my code:

status = True

def kill() :
    confirm = input("Again? (Y/N) : ")
    if confirm == "n":
        status = False

while(status):
    plan_option = input("Which plan are using ? (a/b/c/d/e):   ").lower()
    if plan_option == "a" :
        print("Your current bill is : $90")
        kill() 
    else :
        data_amount = float(input("How much data have you used?          "))

print("===========================") 

def plan_b(x) :
    if x < 10 :
        print("Your current bill is : $60")
    elif x > 10 :
        total = 60 + x*10
        print("Your current bill is : $", total)

def plan_c(x) :
    if x < 5 :
        print("Your current bill is : $40")
    elif x > 5 :
        total = 40 + x*12
        print("Your current bill is : $", total)

def plan_d(x) :
    if x < 2 :
        print("Your current bill is : $30")
    elif x > 2 :
        total =  + x*15
        print("Your current bill is : $", total)

def plan_e(x) :
        total = x*18
        print("Your current bill is : $", total)


if plan_option == "b" :
    plan_b(data_amount)
elif plan_option == "c" :
    plan_c(data_amount)
elif plan_option == "d" :
    plan_d(data_amount)
elif plan_option == "e" :
    plan_e(data_amount)

kill()

So my questions are :

If I enter "n" when the code prompt me, the script won't stop and kept going back to plan_option.
even though the code stops (eventually), it kept prompting me "Again? (Y/N) : " before it kills itself.

Where did I do wrong? Also, am I over-engineering here?

Related: http://stackoverflow.com/questions/291978/short-description-of-python-scoping-rules — miradulo, Jul 01 '16 at 07:09
Rather than use a global for `status`, it would be better if `kill()` returned a status value. — cdarke, Jul 01 '16 at 07:10

Alekhya Vemavarapu · Accepted Answer · 2016-07-01T07:14:01.183

6

You have to declare 'status' as a global variable inorder to update value to
"status = False" in your kill method.

You can do 2 things here:
1. Declare status as global variable
2. Return "status" (which is a local variable) from kill method

You can check the tutorials on how to use global variables. Am not going to provide you the code (for your own good ofcourse).

edited Jul 01 '16 at 07:14

answered Jul 01 '16 at 07:08

Alekhya Vemavarapu

1,145
1
10
26

Thanks! It stops now, but even though the loop stops, it promps **"Again? (Y/N) : "** one more time before it kills itself. Why is that? – Yuka Langbuana Jul 01 '16 at 07:20
@YukaLangbuana That wasn't your original question. Please keep your question focused on _a particular problem_. – miradulo Jul 01 '16 at 07:23
1

@YukaLangbuana that could be because you are calling "kill" again in the last line – Alekhya Vemavarapu Jul 01 '16 at 07:27

score 3 · Answer 2 · answered Jul 01 '16 at 07:08

3

def kill() :
    confirm = input("Again? (Y/N) : ")
    if confirm == "n":
        status = False

This creates a local variable named status, and sets that. The global variable of the same name is unaffected.

Add global status in the function so that it uses the global one instead:

def kill() :
    global status
    confirm = input("Again? (Y/N) : ")
    if confirm == "n":
        status = False

answered Jul 01 '16 at 07:08

RemcoGerlich

30,470
6
61
79

Thanks! It stops now, but even though the loop stops, it promps **"Again? (Y/N) : "** one more time before it kills itself. Why is that? – Yuka Langbuana Jul 01 '16 at 07:22
Because the last line of your program is to call `kill()` one more time. – RemcoGerlich Jul 01 '16 at 07:28

score 1 · Answer 3 · answered Jul 01 '16 at 07:26

I think that you should use less complicated way:

try this model

===>here your function a()<===

def a():
    print("A plan in action")


while True:
    ===> your loop code <===


    your_input = input("> ")
    your_input = your_input.upper()


    if your_input == 'N':
        print("\n** You escaped! **\n")
        break
    elif your_input == "A":
        print("\n** Plan A lunched ! **\n")
        a()
        ===>you can use 'break' to stop the loop here <=== 
    else:
        continue

Muhammad Yaseen Khan · Answer 4 · 2016-07-28T15:05:16.357

0

Two revisions:

Use global status in kill()
If you are comparing confirm == "n", then convert n to lower while taking input

Try this:

def kill() :
    confirm = input("Again? (Y/N) : ").lower()
    if confirm == "n":
        global status
        status = False

edited Jul 28 '16 at 15:05

answered Jul 01 '16 at 07:32

Muhammad Yaseen Khan

799
2
8
23

Python while loop won't end

4 Answers4