How to pass arguements to main to call difference API

Martijen's answer makes sense, but it was missing something crucial that may seem obvious to others but was hard for me to figure out.

In the version where you use argparse, you need to have this line in the main body.

args = parser.parse_args(args)

Normally when you are using argparse just in a script you just write

args = parser.parse_args()

and parse_args find the arguments from the command line. But in this case the main function does not have access to the command line arguments, so you have to tell argparse what the arguments are.

Here is an example

import argparse
import sys

def x(x_center, y_center):
    print "X center:", x_center
    print "Y center:", y_center

def main(args):
    parser = argparse.ArgumentParser(description="Do something.")
    parser.add_argument("-x", "--xcenter", type=float, default= 2, required=False)
    parser.add_argument("-y", "--ycenter", type=float, default= 4, required=False)
    args = parser.parse_args(args)
    x(args.xcenter, args.ycenter)

if __name__ == '__main__':
    main(sys.argv[1:])

Assuming you named this mytest.py To run it you can either do any of these from the command line

python ./mytest.py -x 8
python ./mytest.py -x 8 -y 2
python ./mytest.py 

which returns respectively

X center: 8.0
Y center: 4

or

X center: 8.0
Y center: 2.0

or

X center: 2
Y center: 4

Or if you want to run from another python script you can do

import mytest
mytest.main(["-x","7","-y","6"]) 

which returns

X center: 7.0
Y center: 6.0

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from : https://stackoverflow.com/questions/14500183/in-python-can-i-call-the-main-of-an-imported-module