python - 使用 Python 在 .txt 文件的每一行中 append 特定字符串

Question

我有一个具有以下格式的 .txt 文件:

/Users/my_user/folder1/myfile.dat
/Users/my_user/folder2/myfile.dat
/Users/my_user/folder3/myfile.dat
.
.
.
so on

我想在每行末尾 append 另一个文件夹路径，使其看起来像这样:

/Users/my_user/folder1/myfile.dat,/Users/my_user/folder1/otherfile.dat
/Users/my_user/folder2/myfile.dat,/Users/my_user/folder1/otherfile.dat
/Users/my_user/folder3/myfile.dat,/Users/my_user/folder1/otherfile.dat
.
.
.
so on

到目前为止我已经循环尝试过:

with open("test.txt", "a") as myfile:
    myfile.write("append text")

但我只在文件末尾写入。

Answer 1

您可以使用 re.sub 函数。

append 到每行的开头。

with open("test.txt", "r") as myfile:
    fil = myfile.read().rstrip('\n')
with open("test.txt", "w") as f:
    f.write(re.sub(r'(?m)^', r'append text', fil))

追加到每行末尾。

with open("test.txt", "r") as myfile:
    fil = myfile.read().rstrip('\n')
with open("test.txt", "w") as f:
    f.write(re.sub(r'(?m)$', r'append text', fil))