diy.py

# 写入同学们的捐赠明细：
#file1=open(r'C:\Users\Administrator\Desktop\1.txt','w',encoding='utf-8')
#file1.write('小兰:12本\n')
#file1.write('李文:9本\n')
#file1.write('张伟:16本\n')
#file1.write('小丽:11本\n')
#file1.close()
new_wenjian=''
with open(r'C:\Users\Administrator\Desktop\1.txt','r',encoding='utf-8')as file1:
    for data in file1:
        if '李文:9本' in data:
            data=data.replace('李文:9本','李文:20本')
        new_wenjian+=data
with open(r'C:\Users\Administrator\Desktop\1.txt','w',encoding='utf-8')as file1:
    file1.write(new_wenjian)