argparse-addons

0.12.0 · active · verified Sat Apr 11

argparse-addons is a Python library that provides additional types and actions for the standard library's `argparse` module, enhancing command-line interface creation. The current version is 0.12.0. The project maintains a somewhat active release cadence, with the last update in January 2023.

Warnings

gotcha Calling `parser.parse_args()` at the top level of an imported module can lead to unexpected argument parsing behavior or errors in the main script. Always guard `ArgumentParser` instantiation and `parse_args()` calls within an `if __name__ == "__main__":` block if the module is intended to be imported.
Fix: Wrap `ArgumentParser` creation and `parse_args()` calls in `if __name__ == "__main__":`.
gotcha When a positional argument is defined with `nargs='*'` (zero or more arguments) and also `choices`, providing no values for that argument can result in an 'invalid choice: []' error, because `argparse` attempts to validate an empty list against the defined choices.
Fix: Consider if `nargs='*'` is truly appropriate with `choices` for positional arguments, or explicitly add `[]` to your `choices` (though this might clutter help output). Alternatively, ensure a default is set that is within `choices`.
gotcha The interaction between `default` values and actions like `action='append'` or `action='extend'` can be non-intuitive. Default values might be prepended to user-provided input, making it difficult to completely override the default without custom logic.
Fix: Avoid using `default` directly with `action='append'` or `action='extend'` if the intention is for the user's input to completely replace the default. Instead, handle default list population manually after `parse_args()`.

Install

pip install argparse-addons Install with pip

Imports

Integer
```
from argparse_addons import Integer
```

Quickstart

This quickstart demonstrates how to define an argument using the `Integer` type from `argparse-addons`, enforcing a value within a specified range. It uses a standard `argparse.ArgumentParser` instance.

import argparse
from argparse_addons import Integer

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument(
    '--value', 
    type=Integer(0, 255), 
    help='An integer value between 0 and 255.'
)

args = parser.parse_args(['--value', '128'])
print(f'Parsed value: {args.value}')

# Example of invalid input (will raise an error during parse_args)
# try:
#     parser.parse_args(['--value', '-1'])
# except SystemExit as e:
#     print(f'Error: {e}')

view raw JSON →