Python在子流程调用之前继续运行导入的脚本

Question

Okay, newserial.py is the main script I execute, trackid.py is second script i want to execute through subprocess.call("trackid.py",shell=True) . I placed __init__.py in and all files in the same folder.

Problem: However, when I use: import trackid , it automatically executes the script before it reaches the line: subprocess.call("trackid.py",shell=True) . I read tutorial saying you should place in my code:

def main():
  if__name__=="__main__" 
  ...

Yet, it doesn't help! I put def main(): in both scripts newserial.py and trackid.py

Questions:
How do I stop this from happening?
How do I execute trackid.py as a subprocess and automatically end the script and continue with the remaining line of the main script newserial.py ?
How do I prevent functions with the same name from clashing when I import?
What is the best when to use s ubprocess.call / subprocess.Popen what are all the pipes for?

Answer 1

What is meant by the hint that you've found already is that you should wrap all your code in trackid.py like this:

def mytrackid():
    all your code goes here
    bla print bla

if __name__ == '__main__':
    mytrackid()

All the code that is not within a function or class will be executed at the moment that a module is imported. With

if __name__ == '__main__':

you make sure that this part is only being executed when the module is actually the main module.

Answer 2

If you are only calling trackid.py via subprocess.call() , then you don't need to import it at all.

You import a module only if it contains functions that you wish to call in your script that is doing the importing, so

script1.py :

def myfun():
   do stuff

def myfun2():
   return(results)

script2.py :

import script1

script1.myfun()
print script1.myfun2()

When you import a module any code that is not in a function will be executed, hence the problem you are seeing. The if __name__ == __main__ construct is used, normally, to add code that is run for testing purposes when the script is running standalone.

In this case, putting your code from trackid.py in the if __name__... block will ensure it is only executed when you do your subprocess.call() and not when you import the module but, I'm not sure why you want to do this; the subprocess module is generally used to execute non-python code.

I think what you probably want to do is have trackid.py like my script1 , above where it contains function(s) which you can call from newserial.py after importing it.