使用argparse参数作为关键字参数 [英] Using argparse arguments as keyword arguments

问题描述

比方说，用argparse解析命令行后，我有了一个args命名空间.现在，我想用它来创建一些像这样的对象:

Let's say I have an args namespace after parsing my command line with argparse. Now, I want to use this to create some objects like this:

foo = Foo(bar=args.bar)

不幸的是，我限制了如果设置了关键字参数，则该参数不能为None.现在，我需要检查是否设置了args.bar并采取相应措施:

Unfortunately, I have the restriction that if a keyword argument is set, it must not be None. Now, I need to check if args.bar is set and act accordingly:

if args.bar:
    foo = Foo(bar=args.bar)
else:
    foo = Foo()

这很笨拙，无法扩展更多的参数.我想拥有的是这样的:

This is unwieldy and doesn't scale for more arguments. What I'd like to have, is something like this:

foo = Foo(**args.__dict__)

但是这仍然困扰着我最初的问题，并且对于不是__init__方法的关键字参数的键也不起作用.有没有实现这些目标的好方法?

but this still suffers from my initial problem and additionally doesn't work for keys that are not keyword arguments of the __init__ method. Is there a good way to achieve these things?

推荐答案

您可以尝试以下方法:

>>> defined_args = {k:v for k,v in args._get_kwargs() if v is not None}
>>> foo = Foo(**defined_args)

例如:

>>> import argparse
>>> args = argparse.Namespace(key1=None,key2='value')
>>> {k:v for k,v in args._get_kwargs() if v is not None}
{'key2': 'value'}

但是，请注意，_get_kwargs()不是公共API的一部分，因此将来的发行版/版本中可能会或可能不会提供.

Note, however, that _get_kwargs() is not part of the public API so may or may not be available in future releases/versions.

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