如何在保留空行的同时从 MD 文件中的每一行中删除前导和尾随空格？

Question

我将 Markdown 文本存储在一个变量中，稍后我将其写入 MD 文件。 Markdown 包含尾随和前导空格以及只有空格的行。我试图从变量以及MD 文件中删除空格，但无济于事。

请注意：

• 标题 ## 包含前导空格
• 第 [1] 段包含前导空格
• 段落 [2] 之后的第二行不为空，但包含两个空格（可能在代码块中不可见）
• 段落 [a.] 后跟两个空格

markdown = ''' ## This is a headline

 [1] This is the first paragraph

[2] This is the second paragraph

  
a. This is the third paragraph;  
b. This is the fourth paragraph.'''

with open("output.md", "w") as f_out:
    f_out.write(markdown)

理想情况下，output.md 应该是这样的：

## This is a headline

[1] This is the first paragraph

[2] This is the second paragraph

a. This is the third paragraph;
b. This is the fourth paragraph.

编辑：将@Mortz 接受的答案应用于真实来源，我意识到 Markdown 为 <br> 标签使用了两个空格。因此在这种情况下不需要删除尾随空格。可以使用以下命令删除前导空格：clean_markdown = '\n'.join(_.lstrip() for _ in markdown.split('\n'))

Answer 1

您可以拆分换行符 - '\n' 并重新加入所有条目，去掉前导和尾随空格 -

print(repr(markdown))
#' ## This is a headline\n\n [1] This is the first paragraph\n \n [2] This is the second paragraph\n \n   \n   a. This is the third paragraph;  \n   b. This is the fourth paragraph.'

clean_markdown = '\n'.join(_.strip() for _ in markdown.split('\n'))

print(repr(clean_markdown))
#'## This is a headline\n\n[1] This is the first paragraph\n\n[2] This is the second paragraph\n\n\na. This is the third paragraph;\nb. This is the fourth paragraph.'

然后将此clean_markdown 写入您的文件