How to Use Python argparse Module

09/15/2021

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In this article, you will learn how to use Python argparse module.

Python argparse Module

Python’s argparse module provides an easy way to parse command-line arguments and options in a standardized and convenient way. Here are the basic steps to using argparse:

Import the argparse module:

import argparse

Create an instance of the ArgumentParser class:

parser = argparse.ArgumentParser()

Define the arguments and options your program will accept using the add_argument() method. For example, to add a required positional argument:

parser.add_argument("filename", help="the name of the file to process")

You can also add optional arguments using the — prefix or shorthand options using the – prefix, using the add_argument() method. For example, to add an optional –verbose argument with a shorthand -v option:

parser.add_argument("-v", "--verbose", help="increase output verbosity", action="store_true")

Once all arguments and options are defined, call the parse_args() method to parse the command line arguments and options into a namespace object:

args = parser.parse_args()

You can now access the values of the parsed arguments and options through the attributes of the args object. For example:

print(args.filename)
if args.verbose:
    print("Verbose mode enabled")

Here’s a complete example that shows how to use argparse to accept a filename and a –verbose option:

import argparse

parser = argparse.ArgumentParser()
parser.add_argument("filename", help="the name of the file to process")
parser.add_argument("-v", "--verbose", help="increase output verbosity", action="store_true")
args = parser.parse_args()

print(args.filename)
if args.verbose:
    print("Verbose mode enabled")

Assuming the code above is saved in a file named my_program.py, you could run it from the command line like this: