是否可以仅使用argparse解析一个参数组的参数? [英] Is it possible to only parse one argument group's parameters with argparse?

问题描述

我正在做这样的事情:

parser = argparse.ArgumentParser()

group1 = parser.add_argument_group('group1')
group1.add_argument('--test1', help="test1")

group2 = parser.add_argument_group('group2')
group2.add_argument('--test2', help="test2")

group1_args = group1.parse_args()
group2_args = group2.parse_args()

但是，出现以下错误:

Traceback (most recent call last):
  File "test.py", line 19, in <module>
    group1_args = group1.parse_args()
AttributeError: '_ArgumentGroup' object has no attribute 'parse_args'

有没有一种方法只能获取一个参数组的参数?

Is there a way to only get the arguments for one argument group?

推荐答案

如您的错误消息所示，ArgumentGroup不是解析器，特别是它没有parse_args方法.

As your error message indicates, an ArgumentGroup is not a parser, specifically it doesn't have the parse_args method.

ArgumentParser对象和ArgumentGroup对象共享一个基本的ArgumentContainer类，该类为它们提供诸如add_argument的方法.但是ArgumentParser有很多其他代码. ArgumentGroup实际上只是格式化help的一种帮助.它不会以任何方式影响解析.

ArgumentParser objects and ArgumentGroup objects share a base ArgumentContainer class that gives them methods like add_argument. But an ArgumentParser has a lot of additional code. An ArgumentGroup is really just an aid in formatting the help. It does not affect parsing in any way.

为了增加混乱，mutually_exclusive_group是ArgumentGroup的子类，但仅影响help的usage部分，并通过引发错误消息来影响解析.

To add confusion, a mutually_exclusive_group subclasses ArgumentGroup, but affects only the usage part of the help, and affects parsing by raising an error message.

如果您详细说明了为什么要这样做，我们可以提出一些可行的替代方法.例如，有一种parents机制，可让您insert一个parser转换为另一个.或subparsers通过命令"参数将解析控制传递给子解析器.

If you elaborate on why you want to do this, we could come up with some alternatives that might work. For example there is a parents mechanism, that lets you insert one parser into another. Or subparsers that pass parsing control to a subparsers via 'command' arguments.

https://docs.python.org/3/library/argparse. html#parents

在自己的parent解析器中定义每个组，将使您既可以控制帮助显示又可以控制解析.父母的唯一问题是您必须在某种程度上使用help=False来防止-h选项的重复.

Defining each group in its own parent parser, would let you control both the help display, and parsing. Only problem with parents is that you have to use help=False at some level to prevent the duplication of the -h option.

您可能还需要使用parse_known_args，以便组"解析器不会抱怨它无法识别的参数.

You may also need to use parse_known_args so the 'group' parser does not complain about arguments that it does not recognize.

这是一种显示所有args条目的方法，该条目按参数组分组.我包括2个默认组，可选和位置.它确实利用了解析器的私有"属性.这样做会有一定的风险，但这并不是将来的补丁中可能会更改的事情.

Here's a way of displaying all the args entries, grouped by argument group. I'm including the 2 default groups, optionals and positionals. It does make use of 'private' attributes of the parser. There's a bit of risk in doing so, but this isn't the kind of thing that is likely to be changed in future patches.

import argparse
parser = argparse.ArgumentParser()

group1 = parser.add_argument_group('group1')
group1.add_argument('--test1', help="test1")

group2 = parser.add_argument_group('group2')
group2.add_argument('--test2', help="test2")

args = parser.parse_args('--test1 one --test2 two'.split())

print([g.title for g in parser._action_groups])  # all group titles
print(group1._group_actions)  # arguments/actions of `group1`
print([a.dest for a in group2._group_actions]) # actions for group2

for group in parser._action_groups:
    group_dict={a.dest:getattr(args,a.dest,None) for a in group._group_actions}
    print(group.title, argparse.Namespace(**group_dict))

生产

1513:~/mypy$ python stack31519997.py 
['positional arguments', 'optional arguments', 'group1', 'group2']
[_StoreAction(option_strings=['--test1'], dest='test1', nargs=None, const=None, default=None, type=None, choices=None, help='test1', metavar=None)]
['test2']
('positional arguments', Namespace())
('optional arguments', Namespace(help=None))
('group1', Namespace(test1='one'))
('group2', Namespace(test2='two'))

如果更方便地使用词典版本vars(args). argparse.Namespace(**adict)从字典重新创建名称空间.

If could be more convenient to work with vars(args), the dictionary version. argparse.Namespace(**adict) recreates a namespace from a dictionary.

粗略地说，您要创建自己的dest列表，['test1']和['test2'].

Of coarse you make your own dest lists, ['test1'] and ['test2'].

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