在解析器/子解析器的开头使用argparse.REMAINDER [英] Using argparse.REMAINDER at beginning of parser / sub parser

问题描述

我想实现一个允许我将unittest作为子命令之一运行的arg解析器，将参数盲目传递给unittest.main().例如，

I want to implement an arg parser that allows me to run unittests as one of the sub commands, blindly passing the arguments on to unittest.main(). e.g.,

$ foo.py unittest [args to pass to unittest.main()]

以及其他子命令:

$ foo.py foo ...
$ foo.py bar ...

以argparse的示例为例，该方法有效:

Following argparse's example, this works:

#!/usr/bin/python                                                               
import argparse                                                                 

p = argparse.ArgumentParser(prog='PROG')                                        
p.add_argument('-v', '--verbose', action='store_true')                          
sub = p.add_subparsers(dest='cmd')                                              
foo = sub.add_parser('foo')                                                     
bar = sub.add_parser('bar')                                                     
unittest = sub.add_parser('unittest')                                           
unittest.add_argument('command') # Need to add this to make it work.                                              
unittest.add_argument('args', nargs=argparse.REMAINDER)                         

print(p.parse_args('unittest command -blah blah'.split()))       

输出:

Namespace(args=['-blah', 'blah'], cmd='unittest', command='command', verbose=False)

但这不是.似乎首先需要一个正常"参数:

But this doesn't. It seems to require a "normal" argument first:

#!/usr/bin/python                                                               
import argparse                                                                 

p = argparse.ArgumentParser(prog='PROG')                                        
p.add_argument('-v', '--verbose', action='store_true')                          
sub = p.add_subparsers(dest='cmd')                                              
foo = sub.add_parser('foo')                                                     
bar = sub.add_parser('bar')                                                     
unittest = sub.add_parser('unittest')                                           
unittest.add_argument('args', nargs=argparse.REMAINDER)                         

print(p.parse_args('unittest -blah blah'.split()))             

输出:

$ /tmp/foo.py    
usage: PROG [-h] [-v] {foo,bar,unittest} ...
PROG: error: unrecognized arguments: -blah

我可以做print(p.parse_args('unittest -- -f -g'.split()))，但是要求--失败会破坏argparse.REMAINDER的目的.

I can do print(p.parse_args('unittest -- -f -g'.split())), but requiring -- kind of defeats the purpose of argparse.REMAINDER.

有没有办法让argparse做我想做的事情?还是我只需要手工分析这种情况?

Is there a way to get argparse to do what I want? Or do I just need to hand parse this case?

Python 2.7.5

Python 2.7.5

推荐答案

类似于 http:中讨论的相同问题://bugs.python.org/issue17050 ，argparse.REMAINDER doesn't work as first argument

我4年前的推论仍然成立-在REMAINDER有机会采取行动之前，-blah被归类为可选标志. '-'是较早解析的，但在某种意义上...只是对'*'的概括.而不是一个广泛使用的.对于'subparsers'操作而言，它具有一个nargs='+...'值(argparse.PARSER)-就像REMAINDER，不同之处在于它至少需要一个字符串'cmd'.

My deduction from 4 years ago still holds - the -blah is being classed as an optional's flag even before REMAINDER has a chance to act. '--' is parsed earlier, but ... is, in a sense just a generalization of '*'. And not a widely used one. For what it's worth the 'subparsers' Action has a nargs='+...' value (argparse.PARSER) - it's like REMAINDER except it requires at least one string, the 'cmd'.

尚未执行 http://bugs.python.org/issue9334 中的可能修复程序在.因此，您要么需要自己处理'-blah'，要么使用'-'. parse_known_args也可能适用于您的情况.

The possible fix in http://bugs.python.org/issue9334 has not been acted on. So you either need to handle the '-blah' by itself, or use '--'. parse_known_args might also work in your case.

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