在argparse中使用变量arg名称 [英] Using variable arg names with argparse

问题描述

我有一个上游系统，它使用不同的arg名称来调用我的程序.示例:

I have an upstream system that invokes my program with varying arg names. Example:

foo --xyz1 10 --xyz2 25 --xyz3 31

我希望argparsing的结果是xyz = [10，25，31].

I would like the result of argparsing to be a xyz = [10, 25, 31].

我的args的名称有一个通用前缀，但不幸的是，至少必须具有不同的数字后缀，这也表示顺序.我也没有固定数量的参数.

The names of my args have a common prefix, but unfortunately have to differ at least with a different numeric suffix, which also indicates order. I also don't have a fixed number of args.

是否可以使用argparse对此建模?通过内置功能的某种组合，或者通过重写/插入一些自定义解析器处理，可以提供可用的功能.

Is there a way to model this with argparse? Either with what is available through some combination of built-in capabilities, or by overriding/pluging in some custom parser handling.

推荐答案

我建议进行一些预处理以实现此目的:

I would suggest a bit of pre-processing to achieve this:

代码:

def get_xyz_cmd_line(xyz_cmd_line):
    # build a generator to iterate the cmd_line
    cmd_line_gen = iter(xyz_cmd_line)

    # we will separate the xyz's from everything else
    xyz = []
    remaining_cmd_line = []

    # go through the command line and extract the xyz's
    for opt in cmd_line_gen:
        if opt.startswith('--xyz'):
            # grab the opt and the arg for it
            xyz.append((opt, cmd_line_gen.next()))
        else:
            remaining_cmd_line.append(opt)

    # sort the xyz's and return all of them as -xyz # -xyz # ... 
    return list(it.chain(*[
        ('--xyz', x[1]) for x in sorted(xyz)])) + remaining_cmd_line 

要测试:

import argparse
import itertools as it

parser = argparse.ArgumentParser(description='Get my Option')
parser.add_argument('--an_opt', metavar='N', type=int,
                    help='An option')
parser.add_argument('--xyz', metavar='N', type=int, action='append',
                    help='An option')

cmd_line = "--an_opt 1 --xyz1 10 --xyz3 31 --xyz2 25 ".split()
args = parser.parse_args(get_xyz_cmd_line(cmd_line))
print(args)

输出:

Namespace(an_opt=1, xyz=[10, 25, 31])

要使用:

名义上而不是上面的示例中的固定cmd_line，将使用类似以下内容的名称进行调用:

Nominally instead of a fixed cmd_line as in the above example this would be called with something like:

args = parser.parse_args(get_xyz_cmd_line(sys.argv[1:]))

更新:如果需要--xyz = 31(即=分隔符):

UPDATE: If you need --xyz=31 (ie = separator):

然后您需要更改:

# grab the opt and the arg for it
xyz.append((opt, cmd_line_gen.next()))

收件人:

if '=' in opt:
    xyz.append(tuple(opt.split('=', 1)))
else:
    # grab the opt and the arg for it
    xyz.append((opt, cmd_line_gen.next()))

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