nestargs 0.3.0

Nested arguments parser

nestargs

nestargs is a Python library that defines nested program arguments. It is based on argparse.

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Installation

pip install nestargs

Basic usage

Define program arguments in the same way as argparse. A nested structure can be represented by putting a dot in the program argument name.

import nestargs

parser = nestargs.NestedArgumentParser()

parser.add_argument("--apple.n", type=int)
parser.add_argument("--apple.price", type=float)

parser.add_argument("--banana.n", type=int)
parser.add_argument("--banana.price", type=float)

args = parser.parse_args(
    ["--apple.n=2", "--apple.price=1.5", "--banana.n=3", "--banana.price=3.5"]
)
# => NestedNamespace(apple=NestedNamespace(n=2, price=1.5), banana=NestedNamespace(n=3, price=3.5))

Let's take out only the program argument apple.

args.apple
# => NestedNamespace(n=2, price=1.5)

You can also get each value.

args.apple.price
# => 1.5

If you want a dictionary format, you can get it this way.

vars(args.apple)
# => {'n': 2, 'price': 1.5}

Define program arguments from functions

The function register_arguments can be used to define program arguments from the parameters any function.

In the following example, program arguments with multiple prefixes are defined as the n and price parameters of the function total_price. At this time, the behavior of the program argument is automatically determined according to the default value of the parameter.

import nestargs


def total_price(n=1, price=1.0):
    return n * price


parser = nestargs.NestedArgumentParser()
parser.register_arguments(total_price, prefix="apple")
parser.register_arguments(total_price, prefix="banana")

args = parser.parse_args(
    ["--apple.n=2", "--apple.price=1.5", "--banana.n=3", "--banana.price=3.5"]
)
# => NestedNamespace(apple=NestedNamespace(n=2, price=1.5), banana=NestedNamespace(n=3, price=3.5))

You can call the function with the values obtained from the program arguments as follows:

apple = total_price(**vars(args.apple))
banana = total_price(**vars(args.banana))

print(apple + banana)
# => 13.5