python实现根据目标字符串修改一下行

需求：

根据source和dest两个文件，找出新增的命令行，然后在xml文件中根据命令修改id

输入souce：

ADD 100
SUB 200

输入dest:

MUL 300
DIV 400
ADD 100

　　输入macro：

<tar>MUL</tar>
<id>0</id>
......
<tar>DIV</tar>
<id>0</id>

　　输出：

<tar>MUL</tar>
<id>300</id>
......
<tar>DIV</tar>
<id>400</id>

　　实现代码：

#! /usr/bin/env python
# encoding:utf-8
import re
from bs4 import BeautifulSoup

def chen():
    file1 = 'D:\py\yeah\source.txt'
    file2 = 'D:\py\yeah\dest.txt'
    file3 = 'D:\py\yeah\macro.xml'
    source = []
    dest = []
    with open(file1, 'r') as f_s:
        for line in f_s:
            source.append(line.strip())
    with open(file2, 'r') as f_d:
        for line in f_d:
            dest.append(line.strip())

    result = [item for item in dest if item not in source]  # 获取新增的命令
    print(result)
    '''
        f_xml = open(file3,'r+',encoding ='utf-8')
        soup = BeautifulSoup(f_xml,'xml')
        for item in soup.find_all('tar'):     #找到tar的节点
            next_sibling = item.find_next_sibling() #由于<tar></tar>和<id></id>是兄弟节点，可以通过查找下一个兄弟节点找到<MacroId>
            print(next_sibling.string)  #修改<id></id>的内容
            next_sibling.string = '0'
    '''
    dic ={}
    for res in result:
        dic[re.sub('\d+','',res).strip()] = re.sub('\D+','',res).strip()
    data = []
    with open(file3, 'r', encoding="utf-8") as f3_r:
        lines = f3_r.readlines()
        lineIdx = 0
        while lineIdx < len(lines):
            if re.search('tar', lines[lineIdx]):  # 查找到<CmdName>
                data.append(lines[lineIdx])
                tarstr = re.findall(r"<tar>(.+?)</tar>",lines[lineIdx])
                lineIdx += 1  # 索引到下一行
                if tarstr[0] in dic.keys():
                    lines[lineIdx] = re.sub("\d+", dic[tarstr[0]], lines[lineIdx])  # 将ID替换为目标ID值
                data.append(lines[lineIdx])
            else:
                data.append(lines[lineIdx])
            lineIdx += 1
    with open(file3, 'w', encoding="utf-8") as f3_w:  # 写回原文件
        for item in data:
            f3_w.write(item)

if __name__ == '__main__':
    chen()