python use shell command and send the output

Question

I have a python file name "a.py" and another python file name "b.py". I wanted to run a.py with command in b.py file and I use this codes below:

import os
def b():
 os.system("python a.py")

but a.py has a list name "list_exam" that I want to pass it to b.py through the command line code. I don't know how to pass it in a.py and how to get with command in b.py file.

thanks a lot.

• FlyingTeller: Do you absolutely need to do this from the command line? importing would probably be much easier for this use case
• MMRA: in fact, my main command is os.system("python b.py -c configs/conf.json") and I want to send different config each time. @FlyingTeller
• Jean-François Fabre: serialize/de-serialize? or just use modules... if you have json you can pass more list data in there
• Cezar Cobuz: Possible duplicate of What is the best way to call a Python script from another Python script?

Answer 1

Please don't use shell commands to invoke other Python scripts, it is neither efficient nor scalable.

if a.py:

def do_somthing(param1, param2):
 ...
 list_exam = make_result()
 return list_exam
def main(config):
 do_something(config['param1'], config['param2'])

you can write b.py like this:

import a
def b():
 list_exam = a.do_something(config['param1'], config['param2'])

don't forget to create a __init__.py file in that dir.

Answer 2

You may want to use sys.argv to get command line parameters. Take a look at this: https://www.pythonforbeginners.com/system/python-sys-argv

But, maybe your question is already answered here: Passing a List to Python From Command Line