不要在最后一个位置参数之后解析选项 [英] Don't parse options after the last positional argument
问题描述
我正在为 ssh 命令行客户端编写一个包装器.在 command 的第一个位置参数之后，所有其他选项也应视为位置参数.
I'm writing a wrapper around the ssh command line client. After the first positional argument that's part of command, all further options should also be treated as positional arguments.
在 optparse 下，我相信这可以通过 disable_interspersed_args.
Under optparse, I believe this would be done with disable_interspersed_args.
目前我有这样的事情:
parser = argparse.ArgumentParser()
parser.add_argument('--parallel', default=False, action='store_true')
# maybe allow no command? this would ssh interactively into each machine...
parser.add_argument('command', nargs='+')
args = parser.parse_args()
但如果选项作为命令的一部分传递(例如 my_wrapper ls -l)，它们会被 ArgumentParser 解释为未知选项.错误:无法识别的参数:-l
But if options are passed as part of the command (such as my_wrapper ls -l), they're instead interpreted by ArgumentParser as unknown options. error: unrecognized arguments: -l
如果我使用 parse_known_args(), 选项可能会乱序.
If I use parse_known_args(), the options may be taken out of order.
p = argparse.ArgumentParser()
p.add_argument('-a', action='store_true')
p.add_argument('command', nargs='+')
print(p.parse_known_args())
$ python3 bah.py -b ls -l -a
(Namespace(a=True, command=['ls']), ['-b', '-l'])
这里可以看到ls之前-b的位置已经丢失了，-a已经从命令中解析出来了，这是不想要的.
Here you can see that -b's position before ls has been lost, and -a has been parsed out from the command, which is not desired.
我该怎么做:
- 防止参数在某个点之后被解析?
- 禁用散布参数的解析?
- 允许带前缀的参数作为位置参数使用吗?
推荐答案
我遇到了同样的问题.我在 argparse 错误跟踪器上找到了解决方案:http://code.google.com/p/argparse/issues/detail?id=52
I had the same problem. I found the solution on the argparse bug tracker: http://code.google.com/p/argparse/issues/detail?id=52
解决方案很简单:将 nargs='+'(或 '*')替换为 nargs=argparse.REMAINDER.这个特殊值没有记录在案，但它可以满足您的需求.
The solution is simple: replace nargs='+' (or '*') with nargs=argparse.REMAINDER. This special value is not documented, but it does what you want.
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