Python argparse : Lots of choices results in ugly help output

Question

我有这段代码，我通常很满意:

import argparse

servers = [ "ApaServer", "BananServer", "GulServer", "SolServer", "RymdServer",
            "SkeppServer", "HavsServer", "PiratServer", "SvartServer", "NattServer", "SovServer" ]

parser = argparse.ArgumentParser(description="A program to update components on servers.")
group = parser.add_mutually_exclusive_group()
group.add_argument('-l', '--list', dest="update", action='store_false', default=False, help='list server components')
group.add_argument('-u', '--updatepom', dest="update", action='store_true', help='update server components')
parser.add_argument('-o', '--only', nargs='*', choices=servers, help='Space separated list of case sensitive server names to process')
parser.add_argument('-s', '--skip', nargs='*', choices=servers, help='Space separated list of case sensitive server names to exclude from processing')
args = parser.parse_args()

我喜欢choice=servers 为我验证输入中的服务器名称，这样我就不必这样做了。然而，有这么多有效的选择让帮助输出看起来很糟糕:

usage: args.py [-h] [-l | -u]
               [-o [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]]]
               [-s [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]]]

A program to update components on servers.

optional arguments:
  -h, --help            show this help message and exit
  -l, --list            list server components
  -u, --updatepom       update server components
  -o [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]], --only [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]]
                        Space separated list of case sensitive server names to
                        process
  -s [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]], --skip [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} [{ApaServer,BananServer,GulServer,SolServer,RymdServer,SkeppServer,HavsServer,PiratServer,SvartServer,NattServer,SovServer} ...]]
                        Space separated list of case sensitive server names to
                        exclude from processing

如果我愿意，你会推荐哪种方式:

• 很好的(大部分)自动生成的帮助输出
• 验证提供给 -o 或 -s 选项的条目是否在 servers 中。

奖金:

• 是否可以对服务器名称进行不区分大小写的字符串匹配？

追加

我尝试使用 michaelfilms 的建议，其中 -o -s 选项从上述输出中删除，并添加了这部分:

server optional arguments:
  Valid server names are: ApaServer, BananServer, GulServer, SolServer,
  RymdServer, SkeppServer, HavsServer, PiratServer, SvartServer,
  NattServer, SovServer

我认为它看起来不错，但我真的需要为 -o 和 -s 选项提供帮助，否则用户不会知道它们。所以我还没有完全使用这种方法。

Answer 1

我基本上是在重复 Ernest 所说的 - 为了避免丑陋的长长的选择列表，为基于选择的参数设置 metavar='' (尽管它不会消除参数和逗号(例如 -o , 而不是 -o,)。

然后，您可以在一般描述中详细描述可用的选项(如果您希望它们以明显的缩进形式列出，RawDescriptionHelpFormatter 在此处很有用)。

这段代码:

import argparse

servers = [ "ApaServer", "BananServer", "GulServer", "SolServer", "RymdServer",
            "SkeppServer", "HavsServer", "PiratServer", "SvartServer", "NattServer", "SovServer" ]

parser = argparse.ArgumentParser(description="A program to update components on servers.")
group = parser.add_mutually_exclusive_group()
group.add_argument('-l', '--list', dest="update", action='store_false', default=False, help='list server components')
group.add_argument('-u', '--updatepom', dest="update", action='store_true', help='update server components')
parser.add_argument('-o', '--only', choices=servers, help='Space separated list of case sensitive server names to process.  Allowed values are '+', '.join(servers), metavar='')
parser.add_argument('-s', '--skip', choices=servers, help='Space separated list of case sensitive server names to exclude from processing.  Allowed values are '+', '.join(servers), metavar='')
args = parser.parse_args()

产生以下帮助输出:

usage: run.py [-h] [-l | -u] [-o] [-s]

A program to update components on servers.

optional arguments:
  -h, --help       show this help message and exit
  -l, --list       list server components
  -u, --updatepom  update server components
  -o , --only      Space separated list of case sensitive server names to
                   process. Allowed values are ApaServer, BananServer,
                   GulServer, SolServer, RymdServer, SkeppServer, HavsServer,
                   PiratServer, SvartServer, NattServer, SovServer
  -s , --skip      Space separated list of case sensitive server names to
                   exclude from processing. Allowed values are ApaServer,
                   BananServer, GulServer, SolServer, RymdServer, SkeppServer,
                   HavsServer, PiratServer, SvartServer, NattServer, SovServer

希望这是原始帖子所寻找的。