diy.py

# 写入同学们的捐赠明细：'小兰：12本'、'小丽：11本'、'李文：9本'、'张伟：16本'
new_data=''
with open(r'C:\Users\40690\Desktop\test.txt','r',encoding='utf-8') as file:
    for data in file:
        if '小兰:12本'in data:
            data=data.replace('小兰:12本','小兰:15本')
        if '小丽:11本'in data:
            data=data.replace('小丽:11本','小丽:15本')
        new_data+=data
with open(r'C:\Users\40690\Desktop\test.txt','w',encoding='utf-8') as file:
    file.write(new_data)
with open(r'C:\Users\40690\Desktop\test.txt','r',encoding='utf-8') as file:
    a=file.read()
    print(a)