在追加一个.txt的每一行文件使用Python的特定字符串 [英] Append in each line of a .txt file a specific string using Python

问题描述

我有一个具有以下格式的.txt文件：

I have a .txt file with has the following format:

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

我想在每行的末尾附加为了另一个文件夹路径，使它看起来像这样：

I want to append in the end of each line another folder path in order to make it look like this:

/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

到现在我在一个循环中曾尝试：

Till now I have tried in a loop:

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

但我只在文件的结尾写道。

But i only writes at the end of the file.

推荐答案

您可以使用应用re.sub功能。

You could use re.sub function.

要追加在每行的开始。

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))

要附加在每一行的末尾

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))

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