基于另一个参数向 argparse 添加参数的 Pythonic 方式 [英] Pythonic way for adding parameters to argparse based on another parameter
问题描述
在主函数中,我有一个解析器来验证可选输入:
In the main function, I have a parser which validates optional inputs:
def main():
parser = argparse.ArgumentParser()
parser.add_argument('--platform',required=True)
parser.add_argument('--foo')
parser.add_argument('--bar')
parser.add_argument('--baz')
parser.parse_args()
上面的代码片段是一个示例,仅当我提供 --platform 和 --foo,--bar 或 --baz.
The above snippet is an example which only works when I supply --platform and either --foo,--bar or --baz.
这段代码被不同的组件使用,我们称它们为A、B和C组件.
This code is used by different components, let's call them components A, B and C.
Component A 实际上只指定了 --foo 和 --bar :
Component A actually only specifies --foo and --bar:
python script.py --platform A --foo first_example --bar first_example
Component B 实际上只指定了 --bar 和 --baz :
Component B actually only specifies --bar and --baz:
python script.py --platform B --bar second_example --baz second_exmaple
Component C 实际上只指定了--baz:
Component C actually only specifies --baz:
python script.py --platform C --baz third_example
随着我引入更多提供不同参数的组件,我必须添加到解析器的参数数量会增加.以上只是一个例子,我目前正在处理 20 个左右的论点(将来可能会更多).
As I introduce more components, which provide different arguments, the number of arguments I have to add to the parser increases. The above is just an example and I am currently dealing with 20 or so arguments (will likely be more in the future).
我一直在考虑拥有一个配置文件 (.yaml),我可以在其中定义每个组件需要哪些参数:
I have been thinking about having a configuration file (.yaml) where I define which arguments each component needs:
# parameters.yaml
A:
- foo
- bar
B:
- bar
- baz
C:
- baz
我想简化主函数以查看 --platform 参数,并根据作为参数传递的平台,读取配置并向解析器添加其他参数.
I would like to simplify the main function to look at the --platform argument and, based on which platform has been passed as argument, read the configuration and add additional arguments to the parser.
这是我尝试过的:
def main():
parser = argparse.ArgumentParser()
parser.add_argument('--platform',required=True)
# Read from .yaml file
with open('parameters.yaml') as parameter_file:
parameters = yaml.safe_load(parameter_file)
for argument in parameters[sys.argv[sys.argv.index('--platform') + 1]]:
parser.add_argument(
'--' + argument
)
parser.parse_args()
调用函数:
python script.py --platform C --baz third_example
上述代码有效,但我正在寻找其他 Pythonic 解决方案,因为我是 Python 的初学者.一世不太喜欢必须查看 sys.argv 来确定指定了什么 --platform.这个问题有没有更好的解决方案?
the above code works but I am looking for other Pythonic solutions as I am a beginner with Python. I don't really like having to look at sys.argv to determine what --platform has been specified. Are there any better solutions to this problem?
推荐答案
使用子解析器作为子命令:
With subparsers as sub-commands:
import argparse
def run_command(parser, args):
if args.command == 'A':
print(args)
elif args.command == 'B':
print(args)
elif args.command == 'C':
print(args)
parser = argparse.ArgumentParser(
prog='PROG',
epilog="See '<command> --help' to read about a specific sub-command."
)
subparsers = parser.add_subparsers(dest='command', help='Sub-commands')
A_parser = subparsers.add_parser('A', help='Platform A')
A_parser.add_argument("--foo")
A_parser.add_argument('--bar')
A_parser.set_defaults(func=run_command)
B_parser = subparsers.add_parser('B', help='Platform B')
B_parser.add_argument('--bar')
B_parser.add_argument('--baz')
B_parser.set_defaults(func=run_command)
C_parser = subparsers.add_parser('C', help='Platform C')
C_parser.add_argument('--baz')
C_parser.set_defaults(func=run_command)
args = parser.parse_args()
if args.command is not None:
args.func(parser, args)
else:
parser.print_help()
这会产生:
~ python args.py -h
usage: PROG [-h] {A,B,C} ...
positional arguments:
{A,B,C} Sub-commands
A Platform A
B Platform B
C Platform C
optional arguments:
-h, --help show this help message and exit
See '<command> --help' to read about a specific sub-command.
和
~ python args.py B -h
usage: PROG B [-h] [--bar BAR] [--baz BAZ]
optional arguments:
-h, --help show this help message and exit
--bar BAR
--baz BAZ
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