Is it common to write a lot of code under if __name__ == '__main__': statement

Question

my current coding style is like

import xxx

def fun1()
def fun2()
...

if __name__ == '__main__': 

    task = sys.argv[1]
    if task =='task1':
        do task1
    elif task == 'task2':
        do task2
    ...

my problem is that the part of the code under

if __name__ == '__main__': 

is quite huge comparing to the functions defined above and I was told this is not a good programming style. It is due to the fact that I modify stuff and do experiment in each tasks frequently and I want to separate those part of the code away from functions which are less likely to be modified. I want to learn more advice here, thanks!

Answer 1

Like BusyAnt said, the common way to do it is

import xxx

def fun1()
def fun2()
...



def main():
    task = sys.argv[1]
    if task =='task1':
        do task1
    elif task == 'task2':
        do task2
    ...

if __name__ == '__main__':
    main()

The upside of this is it does not run on import, but main() can still be run from another module or file if so preferred.

Answer 2

It is not forbidden to write a lot of things under if __name__ == '__main__', though it is considered better and more readable to wrap everything up in a main() function. This way, the code in main() isn't executed when you import this module in another module, but you can still choose to run it, by calling imported_script.main().

Your code would then look like this :

import xxx

def fun1()
def fun2()
...


def main():
    task = sys.argv[1]
    if task =='task1':
        do task1
    elif task == 'task2':
        do task2
    ...

if __name__ == '__main__':
    main()

I encourage you to read about what does this if statement do, among the many questions asked about it.