pyparam

pyparam

Powerful parameter processing

Features

• Command line argument parser (with subcommand support)
• Rich type support, including py, json, namespace, etc.
• Type overwriting for parameters from command line
• Arbitrary parsing arguments from command line
• Automatic help page assembling
• Help page customization
• Callbacks for option values
• Parameter loading from configuration files

Installation

pip install -U pyparam

Documentation

https://pwwang.github.io/pyparam/

Basic usage

example.py

from rich import print
from pyparam import Params
# program name, otherwise sys.argv[0]
params = Params(prog='pyparam', desc="An example for %(prog)s")
# adding parameters
params.add_param('i, int', type=int,
                 desc="An integer argument.")
params.add_param('float', default=0.1, # type float implied
                 desc="A float argument.")
params.add_param('str', type=str,
                 desc="A str argument.")
params.add_param('flag', type=bool,
                 desc="A flag argument.")
params.add_param('c,count', type='count',
                 desc="A count argument.")
params.add_param('a', type='auto', type_frozen=False,
                 desc="Value will be automatically casted.")
params.add_param('py', type='py',
                 desc="Value will be evaluated by `ast.literal_eval`.")
params.add_param('json', type='json',
                 desc="Value will be converted using `json.loads`.")
params.add_param('list', type='list',
                 desc="Values will be accumulated.")
params.add_param('path', type='path', required=True,
                 desc="Value will be casted into `pathlib.Path`.",
                 callback=( # check if path exists
                     lambda path: ValueError('File does not exist.')
                     if not path.exists() else path
                 ))
params.add_param('choice', type='choice', default='medium',
                 choices=['small', 'medium', 'large'],
                 desc="One of {choices}.")
params.add_param('config.ncores', default=1, # namespace config implied
                 argname_shorten=False,
                 desc='Number of cores to use.')

print(vars(params.parse()))

Try it out:

python example.py

$ python example.py \
    -i2 \
    --float 0.5 \
    --str abc \
    -ccc \
    -a:int 1 \
    --py "{1,2,3}" \
    --json "{\"a\": 1}" \
    --list 1 2 3 \
    --choice large \
    --path . \
    --config.ncores 4

{
    'i': 2,
    'int': 2,
    'float': 0.5,
    'str': 'abc',
    'flag': False,
    'c': 3,
    'count': 3,
    'a': 1,
    'py': {1, 2, 3},
    'json': {'a': 1},
    'list': [1, 2, 3],
    'path': PosixPath('.'),
    'choice': 'large',
    'config': Namespace(ncores=4)
}

Try more features with:

python -m pyparam

Shell completions

Here is how the command completion in fish works:

Check the documentation, as well as the __main__.py to see how the completion works.