排序argparse帮助字母 [英] Sort argparse help alphabetically

问题描述

我使用Python的（2.7）argparse设施，并想自动排序它通过选项的字母顺序产生帮助。

I am using Python's (2.7) argparse facility and would like to automatically sort the help it produces alphabetically by option.

在默认情况下帮助条目在它们被添加*的顺序进行排序，如：

By default help entries are sorted in the order they are added*, as in:

p = argparse.ArgumentParser(description='Load duration curves and other plots')
p.add_argument('--first', '-f', type=int, default=1, help='First Hour')
p.add_argument('--dur', '-d', type=int, default=-1, help='Duration in Hours. Use -1 for all')
p.add_argument('--title', '-t', help='Plot Title (for all plots), default=file name')
p.add_argument('--interp', '-i', action="store_true", default=True, 
                help='Use linear interpolation for smoother curves')
...
args = p.parse_args()

，当为 python脚本称为-h 生产：

usage: script.py [-h] [--first FIRST] [--dur DUR] [--title TITLE] [--interp]

Load duration curves and other plots

optional arguments:
  -h, --help            show this help message and exit
  --first FIRST, -f FIRST
                        First Hour
  --dur DUR, -d DUR     Duration in Hours. Use -1 for all
  --title TITLE, -t TITLE
                        Plot Title (for all plots), default=file name
  --interp, -i          Use linear interpolation for smoother curves

时能够自动对它们进行排序按字母顺序呢？这将是DUR，首先，H，插补，对称号。

Is it possible to automatically sort them alphabetically instead? This would be dur, first, h, interp, title.

*显然，解决办法是手动加入使用p.add_argument按字母顺序添加的条目维护，但我想避免这样做。

*Obviously the work around is to manually maintain by adding entries using p.add_argument in alphabetical added order but I am trying to avoid doing so.

推荐答案

您可以通过提供一个自定义的 HelpFormatter 类;它的内部被正式无证。这意味着你是你自己，当它从Python版本到版本的兼容性，但我发现界面相当稳定：

You can do this by providing a custom HelpFormatter class; the internals of which are officially undocumented. This means you are on your own when it comes to compatibility from Python version to version, but I find the interface quite stable:

from argparse import HelpFormatter
from operator import attrgetter

class SortingHelpFormatter(HelpFormatter):
    def add_arguments(self, actions):
        actions = sorted(actions, key=attrgetter('option_strings'))
        super(SortingHelpFormatter, self).add_arguments(actions)


p = argparse.ArgumentParser(...
    formatter_class=SortingHelpFormatter,
)

下面我排序的选项字符串（（' - 杜尔'，'-d'）等），但你可以随你挑，以什么要排序的。这个简单的排序选项放单短线最后的选项，如 -h 选项。

Here I sort on the option strings (('--dur', '-d'), etc.), but you could take your pick as to what you want to sort on. This simple sorting option puts the single-dash options last, like the -h option.

它输出：

usage: [-h] [--first FIRST] [--dur DUR] [--title TITLE] [--interp]

Load duration curves and other plots

optional arguments:
  --dur DUR, -d DUR     Duration in Hours. Use -1 for all
  --first FIRST, -f FIRST
                        First Hour
  --interp, -i          Use linear interpolation for smoother curves
  --title TITLE, -t TITLE
                        Plot Title (for all plots), default=file name
  -h, --help            show this help message and exit

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