如何通过main（）函数中的pass命令使代码在Shell中保持打开状态？

Question

I'm trying to learn how to build a web browser bot as half learning half project for someone else and I've hit a snag.

The site I'm using as guide has:

def main():
     pass

Which he claims keeps the shell window open do he can run various functions like get x,y cords of the mouse position and take screen shots.

However when I run my code exactly as he has it in the guide it immediately opens and closes.

What I don't want is something like, "make it so pressing enter closes shell instead", what needs to happen is the window stays open so I can enter various functions.

What am I doing wrong? Am I suppose to just import the code in a different shell and run the functions outside it?

The code:

import os   
import time
import ImageGrab

x_pad = 0   
y_pad = 61

def screenGrab():   
    box = (x_pad,y_pad,x_pad+1919,y_pad+970)    
    im = ImageGrab.grab(box)    
    im.save(os.getcwd() + '\\full_snap__' + str(int(time.time())) + '.png','PNG')

def main(): 
    pass    

if __name__ == '__main__':    
    main()

The guide is: http://code.tutsplus.com/tutorials/how-to-build-a-python-bot-that-can-play-web-games--active-11117

Answer 1

You have three ways:

1. Start the intepreter with the -i option, as suggested by Ulrich in the comments:

    python -i my-script.py 

   This way, the interpreter will be left open as soon as your script finishes execution and a prompt will be shown.

2. Use pdb . This is often used for debugging, and has a different interface than the usual Python prompt. If you're not familiar with it, it might not be the best option in your case. Replace pass with these two lines:

    import pdb pdb.set_trace() 

3. Use code . This will give you an interface much more similar to the usual Python shell and can be an alternative to pdb if you're not familiar with it:

    import code code.interact() 

By the way, you were not doing anything wrong per se. The pass statement is not meant to "halt Python and start a prompt", it's just needed as a filler for functions or loops with an empty body.