Python argparse:很多选择导致难看的帮助输出 [英] Python argparse: Lots of choices results in ugly help output

问题描述

我有这段代码，我对此很满意:

I have this code which I am generally pleased with:

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:

I like that the choice=servers validates the server names in the input for me, so that I won´t have to. However, having so many valid choices makes the help output look terrible:

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:

Which way would you recommend if I want:

• 不错的(主要是)自动生成的帮助输出
• 验证提供给 -o 或 -s 选项的条目在 servers 中.

奖励:

• 是否可以对服务器名称进行不区分大小写的字符串匹配?

附加

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

I tried using michaelfilms suggestion where the -o -s options are removed from the above output and this part is added:

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.

I think it looks pretty good, but I really need to provide help for -o and -s options as the user wouldn´t know about them otherwise. So I am not all the way there yet using this approach.

推荐答案

我基本上是在重复 Ernest 所说的 - 为了避免丑陋的选择列表，为基于选择的参数设置 metavar=''(尽管它不会t 去掉参数和逗号之间的空格(例如 -o , 而不是 -o,).然后你可以在一般描述中详细描述可用的选择 (RawDescriptionHelpFormatter如果您希望它们以明显的缩进列出，则在这里很有用).

I am basically repeating what Ernest said - to avoid the ugly long list of choices, set metavar='' for the choice-based arguments (though it won't get rid of the whitespace between the argument and comma (e.g. -o , instead of -o,). You can then describe available choices in detail in general description (RawDescriptionHelpFormatter is useful here if you want them listed with obvious indentation).

我不明白为什么欧内斯特的回答被否决了.这段代码

I do not understand why Ernest's answer was voted down. This code

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

希望这就是原始帖子所寻找的内容.

This is hopefully what original post was looking for.

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