python - 在 % 之后删除文本文件中的部分行，除非在 python 中前缀为\

Question

我正在尝试从文件中提取 latex 代码，但我不想要注释； (注释以 % 开头)。注释一直到行尾，但我不想删除文字 %(在 \% 中以 \ 开头)。我该怎么做？理想情况下:

   Lamport and has become the dominant method for using \TeX; few
   people write in plain \TeX{} anymore. The current version is
   \LaTeXe. % this is a comment

   % This is a comment; it will not be shown in the final output.
   % The following shows a little of the typesetting power of LaTeX:
   \begin{align}
    E &= mc^2                              \\
    m &= \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}
   \end{align}
   this is a \% literal symbol.

我会得到:

   Lamport and has become the dominant method for using \TeX; few
   people write in plain \TeX{} anymore. The current version is
   \LaTeXe.


   \begin{align}
    E &= mc^2                              \\
    m &= \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}
   \end{align}
   this is a \% literal symbol.

有没有办法用 Python 做到这一点？

在工作解决方案后进行编辑，感谢大家。

   r'(.*)(?<!\\\)%.*'

Answer 1

您可以对 (?<!\\)%.* 进行正则表达式替换，但这很脆弱，例如\verb!%!可能不是评论。