如何使用Python修改文本文件

Question

我有以下文本文件：

1. It’s hard to explain puns to kleptomaniacs because they always take things literally.

2. I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

我使用以下脚本除去数字和换行符：

import re
with open('jokes.txt', 'r+') as original_file:
    modfile = original_file.read()
    modfile = re.sub("\d+\. ", "", modfile)
    modfile = re.sub("\n", "", modfile)
    original_file.seek(0)
    original_file.truncate()
    original_file.write(modfile)

运行脚本后，我的文本文件如下：

It’s hard to explain puns to kleptomaniacs because they always take things literally. I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

我希望文件是：

It’s hard to explain puns to kleptomaniacs because they always take things literally.
I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

如何删除新行而不修补所有行？你知道吗

Answer 1

可以使用一个替换，替换为以下正则表达式：

re.sub(r"\d+\. |(?<!^)\n", "", modfile, flags=re.MULTILINE)

(?<!^)\n将匹配换行符，除非它位于行的开头。标志re.MULTILINE使^匹配行的每个开头。你知道吗

regex101 demo

在代码中：

import re
with open('jokes.txt', 'r+') as original_file:
    modfile = original_file.read()
    midfile = re.sub(r"\d+\. |(?<!^)\n", "", modfile, flags=re.MULTILINE)
    original_file.seek(0)
    original_file.truncate()
    original_file.write(modfile)

---

如果需要，也可以使用负向前看而不是向后看：

r"\d+\. |\n(?!\n)"