Argparse 参数数量限制

Question

我正在尝试将 bash 脚本转换为 python 脚本，并且必须使用 Argparser 创建很多参数。 当我使用此参数运行代码时，我收到错误

'
  File "/home/lmonari/anaconda3/envs/ChemFlowOfficial/lib/python3.9/argparse.py", line 338, in _format_usage
    assert ' '.join(opt_parts) == opt_usage

AssertionError'

如果我随机注释一些参数，则代码可以正常工作。 我是否已达到 Argparse 的最大参数数？我没有在任何地方找到记录的限制

代码：

为命令行创建解析器

parser = argparse.ArgumentParser(add_help=False)

# format the argument groups
parser._action_groups.pop()

# help arguments
help_args = parser.add_argument_group('[ Help ] ')
help_args.add_argument('-h', '--help', action='store_true',
                       help='Show this help message and exit.' )
help_args.add_argument("-H","--Help", action='help',
                    help="Detailed help.")                       

# checking the short help from the terminal_input
terminal_input=sys.argv
if '-h' in terminal_input or '--help' in terminal_input:
    DockFlow_help_short()
    parser.exit()
    
# required arguments
required = parser.add_argument_group('[ Required ] ')
required.add_argument('-p',"---project", metavar='',
                    help="STR : ChemFlow project.")
# required.add_argument("-r","--receptor", metavar='',
#                     help="Receptor's mol2 file.", required=True)
# required.add_argument("-l","--ligand", metavar='',
#                     help="FILE : Ligands  MOL2 file.", required=True) 
# required.add_argument("-dp","--program", metavar='',
#                     help="STR : plants, vina, qvina, smina.", required=True) 

# post processing
post_pro = parser.add_argument_group('[ Post Processing ]')
post_pro.add_argument("--postprocess", metavar='',
                      help="Process DockFlow output for the specified project/protocol/receptor.")
post_pro.add_argument("--postprocess-all", metavar='',
                      help="Process DockFlow output in a ChemFlow project.")
post_pro.add_argument('-n',"--n_poses", metavar='',
                      help="INT : Number of docked poses to keep.")
# post_pro.add_argument("--archive", metavar='',
#                       help="Compress the docking folders for the specified project/protocol/receptor.")
# post_pro.add_argument("--archive_all", metavar='',
#                       help="Compress the docking folders in a ChemFLow project.")


# optional argument
optional = parser.add_argument_group('[ Optional ]')
# optional.add_argument("-t","--test", metavar='',
#                     help="STR : Name for this specific protocol [default].") 
# optional.add_argument("-z",'--zeta', default="It's a trap", metavar='',
#                     help="testline", action=None) 

optional.add_argument('--foo', help=argparse.SUPPRESS)

parser.parse_args()

Answer 1

如果我取消注释所有参数，并在足够宽的屏幕上使用 parser.print_usage() ，我会得到

1155:~/mypy$ python3 stack71486789.py 
usage: stack71486789.py [-h] [-H] [-p] -r  -l  -dp  [--postprocess] [--postprocess-all] [-n] [--archive] [--archive_all] [-t] [-z]

在较窄的屏幕上它尝试将用法分成几行，并点击

1155:~/mypy$ python3 stack71486789.py 
Traceback (most recent call last):
  File "stack71486789.py", line 56, in <module>
    parser.print_usage()
  File "/usr/lib/python3.8/argparse.py", line 2501, in print_usage
    self._print_message(self.format_usage(), file)
  File "/usr/lib/python3.8/argparse.py", line 2467, in format_usage
    return formatter.format_help()
  File "/usr/lib/python3.8/argparse.py", line 294, in format_help
    help = self._root_section.format_help()
  File "/usr/lib/python3.8/argparse.py", line 225, in format_help
    item_help = join([func(*args) for func, args in self.items])
  File "/usr/lib/python3.8/argparse.py", line 225, in <listcomp>
    item_help = join([func(*args) for func, args in self.items])
  File "/usr/lib/python3.8/argparse.py", line 349, in _format_usage
    assert ' '.join(opt_parts) == opt_usage

使用格式化程序很脆弱。如果上面显示的用法太长，请尝试将其拆分。 assert 应该检查分割是否正确完成。元变量把事情搞砸了。这个问题是众所周知的。

如果我注释掉所有 metavar ，则有效的多行用法是：

1202:~/mypy$ python3 stack71486789.py 
usage: stack71486789.py [-h] [-H] [-p PROJECT] -r RECEPTOR -l LIGAND -dp PROGRAM [--postprocess POSTPROCESS]
                        [--postprocess-all POSTPROCESS_ALL] [-n N_POSES] [--archive ARCHIVE] [--archive_all ARCHIVE_ALL]
                        [-t TEST] [-z ZETA]

并且完整帮助

1203:~/mypy$ python3 stack71486789.py 
usage: stack71486789.py [-h] [-H] [-p PROJECT] -r RECEPTOR -l LIGAND -dp PROGRAM [--postprocess POSTPROCESS]
                        [--postprocess-all POSTPROCESS_ALL] [-n N_POSES] [--archive ARCHIVE] [--archive_all ARCHIVE_ALL]
                        [-t TEST] [-z ZETA]

[ Help ] :
  -h, --help            Show this help message and exit.
  -H, --Help            Detailed help.

[ Required ] :
  -p PROJECT, ---project PROJECT
                        STR : ChemFlow project.
  -r RECEPTOR, --receptor RECEPTOR
                        Receptor's mol2 file.
  -l LIGAND, --ligand LIGAND
                        FILE : Ligands MOL2 file.
  -dp PROGRAM, --program PROGRAM
                        STR : plants, vina, qvina, smina.

[ Post Processing ]:
  --postprocess POSTPROCESS
                        Process DockFlow output for the specified project/protocol/receptor.
  --postprocess-all POSTPROCESS_ALL
                        Process DockFlow output in a ChemFlow project.
  -n N_POSES, --n_poses N_POSES
                        INT : Number of docked poses to keep.
  --archive ARCHIVE     Compress the docking folders for the specified project/protocol/receptor.
  --archive_all ARCHIVE_ALL
                        Compress the docking folders in a ChemFLow project.

[ Optional ]:
  -t TEST, --test TEST  STR : Name for this specific protocol [default].
  -z ZETA, --zeta ZETA  testline

没有特殊字符或空白的较短 metavar 也应该可以工作。