argparse fails at dealing with sub-commands receiving global options:
import argparse
p = argparse.ArgumentParser()
p.add_argument('--arg', action='store_true')
s = p.add_subparsers()
s.add_parser('test')
will have p.parse_args('--arg test'.split())
work,
but fails on p.parse_args('test --arg'.split())
.
Anyone aware of a python argument parser that handles global options to sub-commands properly?
>>> from docopt import docopt
>>> usage = """
... usage: prog.py command [--test]
... prog.py another [--test]
...
... --test Perform the test."""
>>> docopt(usage, argv='command --test')
{'--test': True,
'another': False,
'command': True}
>>> docopt(usage, argv='--test command')
{'--test': True,
'another': False,
'command': True}
You can easily add this argument to both parsers (main parser and subcommand parser):
import argparse
main = argparse.ArgumentParser()
subparser = main.add_subparsers().add_parser('test')
for p in [main,subparser]:
p.add_argument('--arg', action='store_true')
print main.parse_args('--arg test'.split()).arg
print main.parse_args('test --arg'.split()).arg
Edit : As @hpaulj pointed in comment, there is also parents
argument which you can pass to ArgumentParser
constructor or to add_parser
method. You can list in this value parsers which are bases for new one.
import argparse
base = argparse.ArgumentParser(add_help=False)
base.add_argument('--arg', action='store_true')
main = argparse.ArgumentParser(parents=[base])
subparser = main.add_subparsers().add_parser('test', parents=[base])
print main.parse_args('--arg test'.split()).arg
print main.parse_args('test --arg'.split()).arg
More examples/docs:
Python argparse - Add argument to multiple subparsers (I'm not sure if this question is not overlaping with this one too much)
Here's a dirty workaround --
import argparse
p = argparse.ArgumentParser()
p.add_argument('--arg', action='store_true')
s = p.add_subparsers()
s.add_parser('test')
def my_parse_args(ss):
#parse the info the subparser knows about; don't issue an error on unknown stuff
namespace,leftover=p.parse_known_args(ss)
#reparse the unknown as global options and add it to the namespace.
if(leftover):
s.add_parser('null',add_help=False)
p.parse_args(leftover+['null'],namespace=namespace)
return namespace
#print my_parse_args('-h'.split()) #This works too, but causes the script to stop.
print my_parse_args('--arg test'.split())
print my_parse_args('test --arg'.split())
This works -- And you could modify it pretty easily to work with sys.argv
(just remove the split string " ss
"). You could even subclass argparse.ArgumentParser
and replace the parse_args
method with my_parse_args
and then you'd never know the difference -- Although subclassing to replace a single method seems overkill to me.
I think however, that this is a lit bit of a non-standard way to use subparsers. In general, global options are expected to come before subparser options, not after.
There's a ton of argument-parsing libs in the Python world. Here are a few that I've seen, all of which should be able to handle address the problem you're trying to solve (based on my fuzzy recollection of them when I played with them last):
解析器具有特定语法: command <global options> subcommand <subcommand ptions>
,您尝试使用选项提供子命令,但您没有定义一个。
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.