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A small utility for simplifying and cleaning up argument parsing scripts.

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Simple, Elegant, Typed Argument Parsing

simple-parsing allows you to transform your ugly argparse scripts into beautifully structured, strongly typed little works of art. This isn't a fancy, complicated new command-line tool either, this simply adds new features to plain-old argparse! Using dataclasses, simple-parsing makes it easier to share and reuse command-line arguments - no more copy pasting!

Supports inheritance, nesting, easy serialization to json/yaml, automatic help strings from comments, and much more!

# examples/demo.py
from dataclasses import dataclass
from simple_parsing import ArgumentParser

parser = ArgumentParser()
parser.add_argument("--foo", type=int, default=123, help="foo help")

@dataclass
class Options:
    """ Help string for this group of command-line arguments """
    log_dir: str                # Help string for a required str argument
    learning_rate: float = 1e-4 # Help string for a float argument

parser.add_arguments(Options, dest="options")

args = parser.parse_args()
print("foo:", args.foo)
print("options:", args.options)
$ python examples/demo.py --log_dir logs --foo 123
foo: 123
options: Options(log_dir='logs', learning_rate=0.0001)
$ python examples/demo.py --help
usage: demo.py [-h] [--foo int] --log_dir str [--learning_rate float]

optional arguments:
  -h, --help            show this help message and exit
  --foo int             foo help (default: 123)

Options ['options']:
   Help string for this group of command-line arguments

  --log_dir str         Help string for a required str argument (default:
                        None)
  --learning_rate float
                        Help string for a float argument (default: 0.0001)

(new) Simplified API:

For a simple use-case, where you only want to parse a single dataclass, you can use the simple_parsing.parse or simple_parsing.parse_known_args functions:

options: Options = simple_parsing.parse(Options)
# or:
options, leftover_args = simple_parsing.parse_known_args(Options)

installation

pip install simple-parsing

Examples

API Documentation (Under construction)

Features

  • Automatic "--help" strings

    As developers, we want to make it easy for people coming into our projects to understand how to run them. However, a user-friendly --help message is often hard to write and to maintain, especially as the number of arguments increases.

    With simple-parsing, your arguments and their descriptions are defined in the same place, making your code easier to read, write, and maintain.

  • Modular, Reusable, Cleanly Grouped Arguments

    (no more copy-pasting)

    When you need to add a new group of command-line arguments similar to an existing one, instead of copy-pasting a block of argparse code and renaming variables, you can reuse your argument class, and let the ArgumentParser take care of adding relevant prefixes to the arguments for you:

    parser.add_arguments(Options, dest="train")
    parser.add_arguments(Options, dest="valid")
    args = parser.parse_args()
    train_options: Options = args.train
    valid_options: Options = args.valid
    print(train_options)
    print(valid_options)
    
    $ python examples/demo.py \
        --train.log_dir "training" \
        --valid.log_dir "validation"
    Options(log_dir='training', learning_rate=0.0001)
    Options(log_dir='validation', learning_rate=0.0001)
    

    These prefixes can also be set explicitly, or not be used at all. For more info, take a look at the Prefixing Guide

  • Argument subgroups

    It's easy to choose between different argument groups of arguments, with the subgroups function!

  • Setting defaults from Configuration files

    Default values for command-line arguments can easily be read from many different formats, including json/yaml!

  • Easy serialization:

    Easily save/load configs to json or yaml!.

  • Inheritance!

    You can easily customize an existing argument class by extending it and adding your own attributes, which helps promote code reuse across projects. For more info, take a look at the inheritance example

  • Nesting!:

    Dataclasses can be nested within dataclasses, as deep as you need!

  • Easier parsing of lists and tuples :

    This is sometimes tricky to do with regular argparse, but simple-parsing makes it a lot easier by using the python's builtin type annotations to automatically convert the values to the right type for you. As an added feature, by using these type annotations, simple-parsing allows you to parse nested lists or tuples, as can be seen in this example

  • Enums support

  • (More to come!)

Examples:

Additional examples for all the features mentioned above can be found in the examples folder