Question

I am trying to work with argparse in python and I do not know how to call the program at command line to see if it works.

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("DocID", type= int, help= "Insert DocID Here")
parser.add_argument("echo", help = "Enter in the FileName to be read")
args = parser.parse_args()
print args

This is my incredibly basic program that I am trying to use just to learn more about how argparse works. I just need to learn how and where to call the program to be able to use the arguments I give it.

Edit: To make my question more clear sorry. I have this code, but I do not know how to call the program as a whole so that I can run it. Like how would I run this in command line? Because when run just in IDLE it produces and error because of a lack of commands

Answer 1

an ArgumentParser’s parse_args method can take a list as input. That list is used for parsing the commandline arguments. So, a common idiom is:

args = parser.parse_args('-a -b -c --value=True'.split())

since str.split returns a list. ('a b c'.split() == ['a', 'b', 'c'])

---

Usually when you add arguments, you do so like this:

parser.add_argument('-a', '--a-long-name', type=int, ...)

Arguments without a - or -- in front are positional arguments, so both of your arguments are positional. You can see a little of what is happening if you do:

args = parser.parse_args(['1','foo'])
print args.DocID # 1
print args.echo  # foo

which is the same as calling your script as python youscript.py 1 foo (without the list inside parse_args).