Python文件替换与拼接异常：仅生成单份输出的解决求助

我有四个文件：file1.txt、file2.txt、file3.txt、file4.txt，还有一个list.txt文件，里面是不同字符串。我想替换file3.txt里的字符串"xxxxxxxx"，尝试用Python拼接所有文件内容并替换后生成output.txt，但只得到一份拼接结果。

现有代码 #

import re

info1 = info2 = info3 = info4 = ""
# Reading information from the first file
with open('file1.txt') as file:
   info1 = file.read()

# Reading information from the second file
with open('file2.txt') as file:
   info2 = file.read()
    
# Reading information from the third file
with open('file3.txt') as file:
   info3 = file.read()

#Reading information from the list file
with open ('mylist.txt') as file:
    mylist = file.readlines()

for string in mylist:
    info3 = re.sub("xxxxxxxxxx", string, info3)
 
with open('file4.txt') as file:
     info4 = file.read()

info1 += info2
info2 += info3
info3 += info4

with open ('output.txt', 'w') as file:
    file.write(info1)
    file.write(info3)  

示例输入 #

• file1.txt内容：

  Hello World
  

• file2.txt内容：

  My name is Darth Vader
  

• file3.txt内容：

  I have come to invade xxxxxxxxxx
  

• file4.txt内容：

  If you only knew the power of dark side. 
  

• list.txt内容：

  tatooine 
  coruscant 
  hoth
  bespin
  

当前输出 #

Hello World
My name is Darth Vader 
I have come to invade tatooine
If you only knew the power of dark side.

期望输出（file1.txt内容仅出现一次） #

Hello World
My name is Darth Vader 
I have come to invade tatooine
If you only knew the power of dark side.
My name is Darth Vader 
I have come to invade coruscant
If you only knew the power of dark side.
My name is Darth Vader 
I have come to invade hoth
If you only knew the power of dark side.
My name is Darth Vader 
I have come to invade bespin
If you only knew the power of dark side.

问题原因与解决方案 #

问题出在循环逻辑和内容处理顺序上：

1. 循环里直接修改info3，每次替换会覆盖之前的结果，最后只保留了最后一次替换的内容
2. 拼接和写入操作都在循环外，所以只生成了一份结果

修改后的代码如下：

import re

# 读取所有固定内容
with open('file1.txt') as file:
    info1 = file.read()

with open('file2.txt') as file:
    info2 = file.read()

# 保存file3的原始模板，每次循环都基于模板替换，避免覆盖
with open('file3.txt') as file:
    info3_template = file.read()

with open('file4.txt') as file:
    info4 = file.read()

with open('mylist.txt') as file:
    mylist = file.readlines()

# 处理输出文件
with open('output.txt', 'w') as output_file:
    # 先写入file1的内容，仅一次
    output_file.write(info1)
    # 遍历每个字符串，生成对应块并写入
    for string in mylist:
        # 去除字符串末尾多余的换行符
        string = string.strip()
        # 用当前字符串替换模板中的占位符
        info3 = re.sub("xxxxxxxxxx", string, info3_template)
        # 拼接并写入file2+替换后的file3+file4
        output_file.write(info2)
        output_file.write(info3)
        output_file.write(info4)
        # 可选：添加换行分隔不同块
        output_file.write('\n')

关键修改点 #

• 单独保存file3.txt的原始模板，每次循环都基于模板重新替换，避免之前的替换结果被覆盖
• 将写入操作放到循环内部，每个字符串对应一次拼接写入
• 用strip()处理list.txt中的字符串，避免多余换行导致格式混乱

内容的提问来源于stack exchange，提问作者DaSnipeKid