How to Use Python argparse Module
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Contents
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:
$ python my_program.py myfile.txt -v
This would print the filename and enable verbose mode.