Ending an infinite while loop

Question

I currently have code that basically runs an infinite while loop to collect data from users. Constantly updating dictionaries/lists based on the contents of a text file. For reference:

while (True):     IDs2=UpdatePoints(value,IDs2)     time.sleep(10) 

Basically, my problem is that I do not know when I want this to end, but after this while loop runs I want to use the information collected, not lose it by crashing my program. Is there a simple, elegant way to simply exit out of the while loop whenever I want? Something like pressing a certain key on my keyboard would be awesome.

Answer 1

You can try wrapping that code in a try/except block, because keyboard interrupts are just exceptions:

try:     while True:         IDs2=UpdatePoints(value,IDs2)         time.sleep(10) except KeyboardInterrupt:     print('interrupted!') 

Then you can exit the loop with CTRL-C.

Answer 2

You could use exceptions. But you only should use exceptions for stuff that isn't supposed to happen. So not for this.

That is why I recommand signals:

import sys, signal def signal_handler(signal, frame):     print("\nprogram exiting gracefully")     sys.exit(0)  signal.signal(signal.SIGINT, signal_handler) 

you should put this on the beginning of your program and when you press ctrl+c wherever in your program it will shut down gracefully

Code explanation:

You import sys and signals. Then you make a function that executes on exit. sys.exit(0) stops the programming with exit code 0 (the code that says, everything went good).

When the program get the SIGINT either by ctrl-c or by a kill command in the terminal you program will shutdown gracefully.