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\Makcoo-Bellcode\Desktop\book.txt","r",encoding="utf-8") as file:
    for data in file:
        if "小强:10本" in data:
            data=data.replace("小强:10本","小强:11本")
        new_data+=data

with open(r"C:\Users\Makcoo-Bellcode\Desktop\book.txt","w",encoding="utf-8") as file:
    file.write(new_data)