如何显示 argparse 中所有子解析器的帮助?

问题描述：

我制作了一个执行很多操作的 Python 脚本，所以它有很多选项，所以我将它划分为也使用父解析器进行公共选项分组的子解析器.

I have made a Python script that is doing a lot of actions, so it has many options, so I divided it to subparsers that also use parent parsers for common options grouping.

我想要一个帮助选项来显示所有命令及其选项的帮助，是否可以不覆盖 format_help 方法?

I want a help option that will show the help for all commands with their options, is it possible without overriding the format_help method?

我看到了一个类似的问题，但是分组不是对我来说很重要，我只想要那里的选项.

I saw a similar question, but the grouping is not critical for me, I just want the options there.

例如:

general_group = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter,add_help=False)
general_group.add_argument('--threads', action='store_true', default=False)
second_group = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter,add_help=False)
second_group.add_argument('--sleep', action='store', default=60, type=int)
parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
subparsers=parser.add_subparsers(dest='action')
subparsers.add_parser('Restart',parents=[general_group,second_group])
subparsers.add_parser('Start',parents=[general_group])

args = parser.parse_args()

在这种情况下，我希望如果有人运行 ./script.py -h 他们会在帮助中看到线程选项.

In this case I would like that if someone runs ./script.py -h they'll see the threads option in the help.

答

问题在于:

subparsers=parser.add_subparsers(dest='action')
subparsers.add_parser('Restart',parents=[general_group,second_group])
subparsers.add_parser('Start',parents=[general_group])

您将 general_group 作为父解析器添加到子解析器，因此主解析器不知道它们，导致 ./script.py -h 不显示--threads.如果你打算把它作为所有子解析器的父级，那么你应该把它作为顶级解析器父级:

You are adding general_group as parent to the subparsers, so the main parser does not know about them, which results in ./script.py -h to not show --threads. If you plan to put it as parent of all the subparsers then you should put it as top parser parent:

parser = argparse.ArgumentParser(parents=[general_group])
subparsers=parser.add_subparsers(dest='action')
subparsers.add_parser('Restart',parents=[second_group])
subparsers.add_parser('Start')

结果:

$ python script.py -h
usage: script.py [-h] [--threads] {Restart,Start} ...

positional arguments:
  {Restart,Start}

optional arguments:
  -h, --help       show this help message and exit
  --threads

但是请注意，在这种情况下，该选项仅是父解析器的一部分，而不是子解析器的一部分，这意味着:

Note however that in this case the option is part only of the parent parser and not the subparsers, which means that the following:

$python script.py --threads Start

是正确的，同时:

$ python script.py Start --threads
usage: script.py [-h] [--threads] {Restart,Start} ...
script.py: error: unrecognized arguments: --threads

因为 --threads 没有被子解析器继承".如果你想在子解析器中也有 --threads 你必须在它的 parents 参数中指定它:

Because --threads is not "inherited" by the subparser. If you want to have --threads also in the subparser you must specify it in its parents argument:

parser = argparse.ArgumentParser(parents=[general_group])
subparsers=parser.add_subparsers(dest='action')
subparsers.add_parser('Restart',parents=[general_group, second_group])
subparsers.add_parser('Start', parents=[general_group])

这应该可以满足您的要求:

This should do what you want:

$ python script.py -h
usage: script.py [-h] [--threads] {Restart,Start} ...

positional arguments:
  {Restart,Start}

optional arguments:
  -h, --help       show this help message and exit
  --threads
$ python script.py Start -h
usage: script.py Start [-h] [--threads]

optional arguments:
  -h, --help  show this help message and exit
  --threads

如何显示 argparse 中所有子解析器的帮助?

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