另一种简单的方法是包含文本包。

例如,

import argparse, textwrap
parser = argparse.ArgumentParser(description='some information',
        usage='use "python %(prog)s --help" for more information',
        formatter_class=argparse.RawTextHelpFormatter)

parser.add_argument('--argument', default=somedefault, type=sometype,
        help= textwrap.dedent('''\
        First line
        Second line
        More lines ... '''))

通过这种方式，我们可以避免在每个输出行前面有很长的空白。

usage: use "python your_python_program.py --help" for more information

Prepare input file

optional arguments:
-h, --help            show this help message and exit
--argument ARGUMENT
                      First line
                      Second line
                      More lines ...

尝试使用RawTextHelpFormatter来保存所有的格式:

from argparse import RawTextHelpFormatter
parser = ArgumentParser(description='test', formatter_class=RawTextHelpFormatter)

它类似于RawDescriptionHelpFormatter，但不是只应用于描述和epilog, RawTextHelpFormatter也应用于所有帮助文本(包括参数)。

我也遇到过类似的问题(Python 2.7.6)。我尝试使用RawTextHelpFormatter将描述部分分解成几行:

parser = ArgumentParser(description="""First paragraph 

                                       Second paragraph

                                       Third paragraph""",  
                                       usage='%(prog)s [OPTIONS]', 
                                       formatter_class=RawTextHelpFormatter)

options = parser.parse_args()

和有:

usage: play-with-argparse.py [OPTIONS]

First paragraph 

                        Second paragraph

                        Third paragraph

optional arguments:
  -h, --help  show this help message and exit

所以RawTextHelpFormatter不是一个解决方案。因为它打印源代码中出现的描述，保留所有空白字符(为了可读性，我想在源代码中保留额外的制表符，但我不想全部打印它们。此外，raw格式化器不会在行太长时换行，例如超过80个字符)。

感谢@Anton，他给了我正确的方向。但是为了格式化描述部分，该解决方案需要稍作修改。

无论如何，需要自定义格式化器。我扩展了现有的HelpFormatter类，并重写了_fill_text方法，如下所示:

import textwrap as _textwrap
class MultilineFormatter(argparse.HelpFormatter):
    def _fill_text(self, text, width, indent):
        text = self._whitespace_matcher.sub(' ', text).strip()
        paragraphs = text.split('|n ')
        multiline_text = ''
        for paragraph in paragraphs:
            formatted_paragraph = _textwrap.fill(paragraph, width, initial_indent=indent, subsequent_indent=indent) + '\n\n'
            multiline_text = multiline_text + formatted_paragraph
        return multiline_text

与来自argparse模块的原始源代码比较:

def _fill_text(self, text, width, indent):
    text = self._whitespace_matcher.sub(' ', text).strip()
    return _textwrap.fill(text, width, initial_indent=indent,
                                       subsequent_indent=indent)

在原始代码中，整个描述都被包装了。在上面的自定义格式化器中，整个文本被分割成几个块，每个块都是独立格式化的。

借助自定义格式化器:

parser = ArgumentParser(description= """First paragraph 
                                        |n                              
                                        Second paragraph
                                        |n
                                        Third paragraph""",  
                usage='%(prog)s [OPTIONS]',
                formatter_class=MultilineFormatter)

options = parser.parse_args()

输出结果为:

usage: play-with-argparse.py [OPTIONS]

First paragraph

Second paragraph

Third paragraph

optional arguments:
  -h, --help  show this help message and exit

另一种简单的方法是包含文本包。

例如,

import argparse, textwrap
parser = argparse.ArgumentParser(description='some information',
        usage='use "python %(prog)s --help" for more information',
        formatter_class=argparse.RawTextHelpFormatter)

parser.add_argument('--argument', default=somedefault, type=sometype,
        help= textwrap.dedent('''\
        First line
        Second line
        More lines ... '''))

通过这种方式，我们可以避免在每个输出行前面有很长的空白。

usage: use "python your_python_program.py --help" for more information

Prepare input file

optional arguments:
-h, --help            show this help message and exit
--argument ARGUMENT
                      First line
                      Second line
                      More lines ...

我承认我发现这是一个非常令人沮丧的经历，因为我看到很多解决方案，我在网上看到很多次这样的问题。但我发现这些解决方案对我来说太复杂了，我想分享我最简单的解决方案。

下面是演示的脚本:

#!/usr/bin/python3
import textwrap
from argparse import ArgumentParser, HelpFormatter

class RawFormatter(HelpFormatter):
    def _fill_text(self, text, width, indent):
        return "\n".join([textwrap.fill(line, width) for line in textwrap.indent(textwrap.dedent(text), indent).splitlines()])

program_descripton = f'''
    FunkyTool v1.0

    Created by the Funky Guy on January 1 2020
    Copyright 2020. All rights reserved.

    Licensed under The Hippocratic License 2.1
    https://firstdonoharm.dev/

    Distributed on an "AS IS" basis without warranties
    or conditions of any kind, either express or implied.

    USAGE:
    '''

parser = ArgumentParser(description=program_descripton, formatter_class=RawFormatter)
args = parser.parse_args()

下面是它在test.py中的样子:

$ ./test.py --help
usage: test.py [-h]

FunkyTool v1.0

Created by the Funky Guy on January 1 2020
Copyright 2020. All rights reserved.

Licensed under The Hippocratic License 2.1
https://firstdonoharm.dev/

Distributed on an "AS IS" basis without warranties
or conditions of any kind, either express or implied.

USAGE:

optional arguments:
  -h, --help  show this help message and exit

所以，所有原始描述中的基本格式都被整齐地保留了下来，我们不得不，唉，使用一个自定义格式化器，但它是一个联机程序。它可以写得更清楚:

class RawFormatter(HelpFormatter):
    def _fill_text(self, text, width, indent):
        text = textwrap.dedent(text)          # Strip the indent from the original python definition that plagues most of us.
        text = textwrap.indent(text, indent)  # Apply any requested indent.
        text = text.splitlines()              # Make a list of lines
        text = [textwrap.fill(line, width) for line in text] # Wrap each line 
        text = "\n".join(text)                # Join the lines again
        return text

但我自己更喜欢写在一行上。

如果存在默认值，以下python 3格式化器将追加默认值并保留行长。

from argparse import ArgumentParser, ArgumentDefaultsHelpFormatter, \ 
                     RawTextHelpFormatter
import textwrap

class CustomArgumentFormatter(ArgumentDefaultsHelpFormatter, RawTextHelpFormatter):
    """Formats argument help which maintains line length restrictions as well as appends default value if present."""

    def _split_lines(self, text, width):
        text = super()._split_lines(text, width)
        new_text = []

        # loop through all the lines to create the correct wrapping for each line segment.
        for line in text:
            if not line:
                # this would be a new line.
                new_text.append(line)
                continue

            # wrap the line's help segment which preserves new lines but ensures line lengths are
            # honored
            new_text.extend(textwrap.wrap(line, width))

        return new_text

然后用你的新格式化器创建你的参数解析器:

my_arg_parser = ArgumentParser(formatter_class=CustomArgumentFormatter)
# ... add your arguments ...
print(my_arg_parser.format_help())