View source for Argh: Organize your command line arguments

Argh helps to handle command line arguments in a big way. Don’t use the build-in Python stuff for that.

Questions to [mailto:davrot@uni-bremen.de David Rotermund]<syntaxhighlight lang="shell">pip install argh</syntaxhighlight>

== Simple example ==

=== No argument is required ===
The arguments are now only optional for the function call:<syntaxhighlight lang="python">import argh


def main(first_parameter: int = 1, second_parameter: int = 2, third_parameter: bool = True) -> None:
    print("Main")


if __name__ == "__main__":
    argh.dispatch_command(main)</syntaxhighlight><syntaxhighlight lang="shell">python test.py</syntaxhighlight>Output<syntaxhighlight lang="shell">Main</syntaxhighlight><syntaxhighlight lang="shell">python test.py --help</syntaxhighlight>Output<syntaxhighlight lang="shell">usage: test.py [-h] [-f FIRST_PARAMETER] [-s SECOND_PARAMETER] [-t]

options:
  -h, --help            show this help message and exit
  -f FIRST_PARAMETER, --first-parameter FIRST_PARAMETER
                        1
  -s SECOND_PARAMETER, --second-parameter SECOND_PARAMETER
                        2
  -t, --third-parameter
                        True</syntaxhighlight>Note: For boolean parameters using the option switches them to the other state. Here '''python test.py''' sets '''third-parameter=True''' and '''python test.py -t''' sets '''third-parameter=False'''.

=== One argument is required ===
<syntaxhighlight lang="python">import argh


def main(first_parameter: int, second_parameter: int = 2, third_parameter: bool = True) -> None:
    print("Main")


if __name__ == "__main__":
    argh.dispatch_command(main)</syntaxhighlight><syntaxhighlight lang="shell">python test.py</syntaxhighlight>Output<syntaxhighlight lang="shell">usage: test.py [-h] [-s SECOND_PARAMETER] [-t] first-parameter
test.py: error: the following arguments are required: first-parameter</syntaxhighlight><syntaxhighlight lang="shell">python test.py 1</syntaxhighlight>Output<syntaxhighlight lang="shell">Main</syntaxhighlight>

== More than one function ==
Sometimes we have a collection of function. This is how we select one of those:<syntaxhighlight lang="python">import argh


def main_1(
    first_parameter: int = 1, second_parameter: int = 2, third_parameter: bool = True
) -> None:
    print("Main 1")


def main_2(first_parameter: int = 1) -> None:
    print("Main 2")


if __name__ == "__main__":
    parser = argh.ArghParser()
    parser.add_commands([main_1, main_2])
    parser.dispatch()</syntaxhighlight><syntaxhighlight lang="shell">python test.py</syntaxhighlight>Output<syntaxhighlight lang="shell">usage: test.py [-h] {main-1,main-2} ...</syntaxhighlight><syntaxhighlight lang="shell">python test.py main-1
python test.py main-2</syntaxhighlight>Output:<syntaxhighlight lang="shell">Main 1
Main 2</syntaxhighlight><syntaxhighlight lang="shell">python test.py main-1 --help
python test.py main-2 --help</syntaxhighlight>Output:<syntaxhighlight lang="shell">usage: test.py main-1 [-h] [-f FIRST_PARAMETER] [-s SECOND_PARAMETER] [-t]

options:
  -h, --help            show this help message and exit
  -f FIRST_PARAMETER, --first-parameter FIRST_PARAMETER
                        1
  -s SECOND_PARAMETER, --second-parameter SECOND_PARAMETER
                        2
  -t, --third-parameter
                        True

usage: test.py main-2 [-h] [-f FIRST_PARAMETER]

options:
  -h, --help            show this help message and exit
  -f FIRST_PARAMETER, --first-parameter FIRST_PARAMETER
                        1</syntaxhighlight>

== Reference ==

* [https://argh.readthedocs.io/en/latest/reference.html Argh]