Is there a method that tells my program to quit?

python exit quit
Kudu picture Kudu · May 13, 2010 · Viewed 219k times · Source

For the "q" (quit) option in my program menu, I have the following code:

elif choice == "q":
    print()

That worked all right until I put it in an infinite loop, which kept printing blank lines. Is there a method that can quit the program? Else, can you think of another solution?

Answer

Greg Hewgill picture Greg Hewgill · May 13, 2010

One way is to do:

sys.exit(0)

You will have to import sys of course.

Another way is to break out of your infinite loop. For example, you could do this:

while True:
    choice = get_input()
    if choice == "a":
        # do something
    elif choice == "q":
        break

Yet another way is to put your main loop in a function, and use return:

def run():
    while True:
        choice = get_input()
        if choice == "a":
            # do something
        elif choice == "q":
            return

if __name__ == "__main__":
    run()

The only reason you need the run() function when using return is that (unlike some other languages) you can't directly return from the main part of your Python code (the part that's not inside a function).

Related questions

How to exit from Python without traceback?

I would like to know how to I exit from Python without having an traceback dump on the output. I still want want to be able to return an error code but I do not want to display the traceback …

Read More
How do I abort the execution of a Python script?

I have a simple Python script that I want to stop executing if a condition is met. For example: done = True if done: # quit/stop/exit else: # do other stuff Essentially, I am looking for something that behaves equivalently to …

Read More
Difference between exit() and sys.exit() in Python

In Python, there are two similarly-named functions, exit() and sys.exit(). What's the difference and when should I use one over the other?

Read More