python - 如何根据正则表达式条件编辑文本文件的行？

Question

import re

re_for_identificate_1 = r""

with open("data_path/filename_1.txt","r+") as file:
    for line in file:
        #replace with a substring adding a space in the middle
        line = re.sub(re_for_identificate_1, " milesimo", line)

        #replace in txt with the fixed line

示例filename_1.txt:

unmilesimo primero
1001°

dosmilesimos quinto
2005°

tresmilesimos
3000°

nuevemilesimos doceavo
9012°

我需要的正确输出文件是这样的:

重写输入 filename_1.txt

un milesimo primero
1001°

dos milesimos quinto
2005°

tres milesimos
3000°

nueve milesimos doceavo
9012°

我需要的正则表达式是什么？在输入文件中将固定行替换到其原始位置的最佳方法是什么？

Answer 1

您可以使用 file.seek(0)转到文件的开头，然后写入数据并截断文件。像这样:

import re

re_for_identificate_1 = "(?<!^)milesimo"

tmp = ""
with open("data.txt", "r+") as file:
    for line in file:
        line = re.sub(re_for_identificate_1, " milesimo", line)
        tmp += line
    file.seek(0)
    file.write(tmp)
    file.truncate()

您要使用的正则表达式是 "(?<!^)milesimo"用“milesimo”替换“milesimo”的每个实例，但不是在一行的开头。