python calling a module that uses argparser

Question

This is probably a silly question, but I have a python script that current takes in a bunch of arguements using argparser and I would like to load this script as a module in another python script, which is fine. But I am not sure how to call the module as no function is defined; can I still call it the same way I do if I was just invoking it from cmd?

Here is the child script:

import argparse as ap from subprocess import Popen, PIPE  parser = ap.ArgumentParser(     description='Gathers parameters.') parser.add_argument('-f', metavar='--file', type=ap.FileType('r'), action='store', dest='file',                     required=True, help='Path to json parameter file') parser.add_argument('-t', metavar='--type', type=str, action='store', dest='type',                     required=True, help='Type of parameter file.') parser.add_argument('-g', metavar='--group', type=str, action='store', dest='group',                     required=False, help='Group to apply parameters to') # Gather the provided arguements as an array. args = parser.parse_args()  ... Do stuff in the script 

and here is the parent script that I want to invoke the child script from; it also uses arg parser and does some other logic

from configuration import parameterscript as paramscript  # Can I do something like this? paramscript('parameters/test.params.json', test) 

Inside the configuration directory, I also created an init.py file that is empty.

Answer 1

The first argument to parse_args is a list of arguments. By default it's None which means use sys.argv. So you can arrange your script like this:

import argparse as ap  def main(raw_args=None):     parser = ap.ArgumentParser(         description='Gathers parameters.')     parser.add_argument('-f', metavar='--file', type=ap.FileType('r'), action='store', dest='file',                         required=True, help='Path to json parameter file')     parser.add_argument('-t', metavar='--type', type=str, action='store', dest='type',                         required=True, help='Type of parameter file.')     parser.add_argument('-g', metavar='--group', type=str, action='store', dest='group',                         required=False, help='Group to apply parameters to')     # Gather the provided arguements as an array.     args = parser.parse_args(raw_args)     print(vars(args))   # Run with command line arguments precisely when called directly # (rather than when imported) if __name__ == '__main__':     main() 

And then elsewhere:

from first_module import main  main(['-f', '/etc/hosts', '-t', 'json']) 

Output:

{'group': None, 'file': <_io.TextIOWrapper name='/etc/hosts' mode='r' encoding='UTF-8'>, 'type': 'json'} 

Answer 2

There may be a simpler and more pythonic way to do this, but here is one possibility using the subprocess module:

Example:

child_script.py

import argparse  parser = argparse.ArgumentParser() parser.add_argument("-n", "--name", help="your name") args = parser.parse_args()  print("hello there {}").format(args.name) 

Then another Python script can call that script like so:

calling_script.py:

import subprocess  # using Popen may suit better here depending on how you want to deal # with the output of the child_script. subprocess.call(["python", "child_script.py", "-n", "Donny"]) 

Executing the above script would give the following output:

"hello there Donny"