python argparse - passing list to argparse without command line

Question

I am trying to make use of an argument handler that I wrote using argparse from within another python script. I would like to call it by passing it a list of arguments. Here is a simple example:

def argHandler(argv):

    import argparse

    parser = argparse.ArgumentParser(description='Test argument parser')

    parser.add_argument('foo', action='store',type=str)
    parser.add_argument('bar', action='store',type=str)
    parser.add_argument('-nee','--knightssaynee',action='store',type=str)

    args = parser.parse_args()

    return args.foo, args.bar, args.nee

if __name__=='__main__':

    argList = ['arg1','arg2','-nee','arg3']

    print argHandler(argList)

This returns a:

usage: scratch.py [-h] [-nee KNIGHTSSAYNEE] foo bar
scratch.py: error: too few arguments

It seems to me that the function that I define should take a list of arguments and flags, and return a namespace. Am I wrong?

Martijn Pieters · Accepted Answer · 2015-08-22 09:32:09Z

3

You need to pass those arguments to the parser.parse_args() method:

args = parser.parse_args(argv)

From the ArgumentParser.parse_args() documentation:

ArgumentParser.parse_args(args=None, namespace=None)

[...]

By default, the argument strings are taken from sys.argv [...]

Note the args argument there. You may want to make the argv argument to your argHandler() function default to None as well; that way you don't have to pass in an argument and end up with the same default None value:

def argHandler(argv=None):

edited Aug 22, 2015 at 9:32

answered Aug 22, 2015 at 9:23

Martijn Pieters

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1 Comment

YoungPadawan Over a year ago

That worked! Thanks, I just needed to change: args = parser.parse_args() to args = parser.parse_args(argv) in my code

MhP · Accepted Answer · 2015-08-22 09:51:45Z

-1

another way i get input to program is from json file with key value pair and using json load library to load contents of file as json object.

answered Aug 22, 2015 at 9:51

MhP

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1 Comment

BlackJack Over a year ago

And this has to do what exactly with the question?

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