Code for How to Use the Argparse Module in Python Tutorial

1_simple_example.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument('input', help='Input file to process.')

args = parser.parse_args()
print(f'Processing file: {args.input}')

2.2_default_and_required.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument('input', help='Input file to process.')
# parser.add_argument('-o', '--output', default='output.txt', help='Output file.')
parser.add_argument('-o', '--output', required=True, help='Output file.')

args = parser.parse_args()
print(f'Processing file: {args.input}')
print(f"Writing to file: {args.output}")

2.3_choices.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument('input', help='Input file to process.')
parser.add_argument('-m', '--mode', choices=['add', 'subtract', 'multiply', 'divide'], help='Calculation mode.')

args = parser.parse_args()
print(f'Processing file: {args.input}')
print(f"Mode: {args.mode}")

2.5_nargs.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument('--values', nargs=3)
# parser.add_argument('--value', nargs='?', default='default_value')
# parser.add_argument('--values', nargs='*')
# parser.add_argument('--values', nargs='+')

args = parser.parse_args()
print(f"Values: {args.values}")

2.6_builtin_actions.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument('--foo', action='store', help='Store the value of foo.')
parser.add_argument('--enable', action='store_true', help='Enable the feature.')
parser.add_argument('--disable', action='store_false', help='Disable the feature.')
parser.add_argument('--level', action='store_const', const='advanced', help='Set level to advanced.')
parser.add_argument('--values', action='append', help='Append values to a list.')
parser.add_argument('--add_const', action='append_const', const=42, help='Add 42 to the list.')
parser.add_argument('-v', '--verbose', action='count', help='Increase verbosity level.')
args = parser.parse_args()
print(f"Values: {args.values}")
print(f"Verbosity: {args.verbose}")

2.6_custom_actions.py

import argparse

class CustomAction(argparse.Action):
    def __call__(self, parser, namespace, values, option_string=None):
        # Perform custom processing on the argument values
        processed_values = [value.upper() for value in values]

        # Set the attribute on the namespace object
        setattr(namespace, self.dest, processed_values)

# Set up argument parser and add the custom action
parser = argparse.ArgumentParser(description='Custom argument action example.')
parser.add_argument('-n', '--names', nargs='+', action=CustomAction, help='A list of names to be processed.')

args = parser.parse_args()
print(args.names)

2.7_argument_types.py

import argparse

parser = argparse.ArgumentParser(description='A simple argparse example.')
parser.add_argument("-r", "--ratio", type=float)
args = parser.parse_args()
print(f"Ratio: {args.ratio}")

3.3_subcommand_example.py

import argparse

parser = argparse.ArgumentParser(description='A subcommand example.')
subparsers = parser.add_subparsers(help='Subcommand help')

list_parser = subparsers.add_parser('list', help='List items')
add_parser = subparsers.add_parser('add', help='Add an item')
add_parser.add_argument('item', help='Item to add')

args = parser.parse_args()

4.1_file_renamer.py

import argparse
import os

# Rename function
def rename_files(args):
    # Your file renaming logic here
    print(f"Renaming files in {args.path}...")
    print(f"Prefix: {args.prefix}")
    print(f"Suffix: {args.suffix}")
    print(f"Replace: {args.replace}")
    os.chdir(args.path)
    for file in os.listdir():
        # Get the file name and extension
        file_name, file_ext = os.path.splitext(file)
        # Add prefix
        if args.prefix:
            file_name = f"{args.prefix}{file_name}"
        # Add suffix
        if args.suffix:
            file_name = f"{file_name}{args.suffix}"
        # Replace substring
        if args.replace:
            file_name = file_name.replace(args.replace[0], args.replace[1])
        # Rename the file
        print(f"Renaming {file} to {file_name}{file_ext}")
        os.rename(file, f"{file_name}{file_ext}")
        
# custom type for checking if a path exists
def path_exists(path):
    if os.path.exists(path):
        return path
    else:
        raise argparse.ArgumentTypeError(f"Path {path} does not exist.")
    
    
# Set up argument parser
parser = argparse.ArgumentParser(description='File renaming tool.')
parser.add_argument('path', type=path_exists, help='Path to the folder containing the files to rename.')
parser.add_argument('-p', '--prefix', help='Add a prefix to each file name.')
parser.add_argument('-s', '--suffix', help='Add a suffix to each file name.')
parser.add_argument('-r', '--replace', nargs=2, help='Replace a substring in each file name. Usage: -r old_string new_string')

args = parser.parse_args()

# Call the renaming function
rename_files(args)

4.2_simple_calculator.py

import argparse

# Operation functions
def add(args):
    print(args.x + args.y)

def subtract(args):
    print(args.x - args.y)

def multiply(args):
    print(args.x * args.y)

def divide(args):
    print(args.x / args.y)

# Set up argument parser
parser = argparse.ArgumentParser(description='Command-line calculator.')
subparsers = parser.add_subparsers()

# Add subcommands
add_parser = subparsers.add_parser('add', help='Add two numbers.')
add_parser.add_argument('x', type=float, help='First number.')
add_parser.add_argument('y', type=float, help='Second number.')
add_parser.set_defaults(func=add)

subtract_parser = subparsers.add_parser('subtract', help='Subtract two numbers.')
subtract_parser.add_argument('x', type=float, help='First number.')
subtract_parser.add_argument('y', type=float, help='Second number.')
subtract_parser.set_defaults(func=subtract)

multiply_parser = subparsers.add_parser('multiply', help='Multiply two numbers.')
multiply_parser.add_argument('x', type=float, help='First number.')
multiply_parser.add_argument('y', type=float, help='Second number.')
multiply_parser.set_defaults(func=multiply)

divide_parser = subparsers.add_parser('divide', help='Divide two numbers.')
divide_parser.add_argument('x', type=float, help='First number.')
divide_parser.add_argument('y', type=float, help='Second number.')
divide_parser.set_defaults(func=divide)

args = parser.parse_args()
args.func(args)