使用 argparse 的组之间的 Python 依赖关系 [英] Python dependencies between groups using argparse

问题描述

我开始学习 Python，现在我正在学习 argparse 的巨大好处.使用 argparse，我创建了两组参数:group_list 和 group_simulate.每个组都有自己的参数——用户只能在每个组中指定一个参数(使用 parser.add_mutually_exclusive_group() 实现).

I started to learn Python, and now I'm learning the great benefits of argparse. Using argparse, I have created two groups of arguments: group_list and group_simulate. Each of the groups has its own arguments -- the user can specify only one argument in each group (achieved using parser.add_mutually_exclusive_group()).

现在，如果用户从两个 groupgs 中指定参数而不是仅从其中一个中指定参数，我的目标就会出现语法错误——我想通过使用 argparse 的功能而不是通过编写一个方法，询问是否指定 this 和 this 打印语法错误.

And now my target is present a syntax error if the user specified arguments from both groupgs and not from only one of them -- I want to achieve this by using the capabilities of argparse and not by writing a method that asks if this and this was specified print syntax error.

import argparse
parser = argparse.ArgumentParser(
        description='this is the description',
        epilog="This is the epilog",
        argument_default=argparse.SUPPRESS  
        )

parser.add_argument('-v', '--verbose', help='verbose', action='store_true', default=False)

group_list = parser.add_mutually_exclusive_group()
group_list.add_argument('-m', help='list only modules', action='store_const', dest='list', const='modules', default='all')
group_list.add_argument('-p', help='list only ports', action='store_const', dest='list', const='ports', default='all')
group_list.add_argument('--list', help='list only module or ports', choices=['modules','ports'], metavar='<modules/ports>', default='all')

group_simulate = parser.add_mutually_exclusive_group()
group_simulate.add_argument('-M', help='simulate module down', nargs=1, metavar='module_name', dest='simulate')
group_simulate.add_argument('-P', help='simulate FC port down', nargs=1, metavar='fc_port_name', dest='simulate')
group_simulate.add_argument('-I', help='simulate iSCSI port down', nargs=1, metavar='iSCSI_port_name', dest='simulate')
group_simulate.add_argument('--simulate', help='simulate module or port down', nargs=1, dest='simulate')

args = parser.parse_args()

print args

所以更具体地说:

允许:

test.py
output: Namespace(list='all', verbose=False)
test.py -m
output: Namespace(list='modules', verbose=False)
test.py -P asfasf
output: Namespace(P=['asfasf'], list='all', verbose=False)

不允许:

test.py -m -P asfsaf
expected output: <the help message>
test.py -P asfasf -m
expected output: <the help message>

我尝试使用 argparse 中的 add_subparsers 选项来实现想要的目标，但没有成功.

I have tried to achieve the wanted target with the option of add_subparsers from argparse but without any success.

所以我的问题是如何实现这种情况?

So my question is how to achieve this situation?

推荐答案

您可以使用一个共同的互斥组作为两个子组的根":

You can use a common mutually-exclusive-group as "root" of the two subgroups:

import argparse
parser = argparse.ArgumentParser(
        description='this is the description',
        epilog="This is the epilog",
        argument_default=argparse.SUPPRESS  
        )

parser.add_argument('-v', '--verbose', help='verbose', action='store_true', default=False)

root_group = parser.add_mutually_exclusive_group()

group_list = root_group.add_mutually_exclusive_group()
group_list.add_argument('-m', help='list only modules', action='store_const', dest='list', const='modules', default='all')
group_list.add_argument('-p', help='list only ports', action='store_const', dest='list', const='ports', default='all')
group_list.add_argument('--list', help='list only module or ports', choices=['modules','ports'], metavar='<modules/ports>', default='all')

group_simulate = root_group.add_mutually_exclusive_group()
group_simulate.add_argument('-M', help='simulate module down', nargs=1, metavar='module_name', dest='simulate')
group_simulate.add_argument('-P', help='simulate FC port down', nargs=1, metavar='fc_port_name', dest='simulate')
group_simulate.add_argument('-I', help='simulate iSCSI port down', nargs=1, metavar='iSCSI_port_name', dest='simulate')
group_simulate.add_argument('--simulate', help='simulate module or port down', nargs=1, dest='simulate')

args = parser.parse_args()

print args

结果:

$ python test.py -m -P asfafs
usage: test.py [-h] [-v] [[-m | -p | --list <modules/ports>]
                [-M module_name | -P fc_port_name | -I iSCSI_port_name | --simulate SIMULATE]
test.py: error: argument -P: not allowed with argument -m 

$ python test.py -m -p
usage: test.py [-h] [-v] [[-m | -p | --list <modules/ports>]
                [-M module_name | -P fc_port_name | -I iSCSI_port_name | --simulate SIMULATE]
test.py: error: argument -p: not allowed with argument -m

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