问题
Say I have a namespace args that I obtain from calling parser.parse_args(), which parses the command line arguments.
How can I import all variables from this namespace to my current namespace?
e.g.
parser.add_argument('-p', '--some_parameter', default=1)
args = parser.parse_args()
# ... code to load all variables defined in the namespace args ...
print some_parameter
I could certainly do:
some_parameter = args.some_parameter
but if I have a large number of parameters I would need one such line for each parameter.
Is there another way of importing variables from a namespace without having to go through them one by one?
PS: from args import * does not work.
PS2: I am aware that this is a bad practice, but this can help in some corner cases, such us when prototyping code and tests very quickly.
回答1:
Update your local namespace with the result of the vars() function:
globals().update(vars(args))
This is generally not that great an idea; leave those attributes in the namespace instead.
You could create more problems than you solved with this approach, especially if you accidentally configure arguments with a dest name that shadows a built-in or local you care about, such as list or print or something. Have fun hunting down that bug!
Tim Peters already stated this in his Zen of Python:
Namespaces are one honking great idea -- let's do more of those!
回答2:
Probably the worst idea ever: since you can pass an arbitrary object to parse_args(), pass the __builtins__ module, so that all attributes can be looked up as local variables.
p = argparse.ArgumentParser()
p.add_argument("--foo")
p.parse_args( "--foo bar".split(), __builtins__)
print foo
This will even "work" for parameters whose destinations aren't valid Python identifiers:
# To use the example given by Francis Avila in his comment on Martijn Pieters' answer
getattr(__builtins__, '2my-param')
来源：https://stackoverflow.com/questions/14697158/importing-variables-from-a-namespace-object-in-python