diy.py

# 写入同学们的捐赠明细：'小兰：12本'、'小丽：11本'、'李文：
# jj=open(r"C:\Users\123\Desktop\新建文件夹\book.txt","w""utf-8")
# jj.write("小兰:12本")
# jj.write("小丽:11本")
# jj.write("李文:9本")
# jj.write("张伟:16本")
# jj.close()
with open(r"C:\Users\123\Desktop\新建文件夹\book.txt","r""utf-8") as jj:
    for data in jj:
        if '小强:12本' in data:
            data=data.replace('小强:12本','小强:11本')
            new_data+=data
with open(r"C:\Users\123\Desktop\新建文件夹\book.txt","w""utf-8") as jj:
    jj.write(new_data)
vwith open(r"C:\Users\123\Desktop\新建文件夹\book.txt","r""utf-8") as jj:
    a=jj.read()
    print(a)
           

    # jj.write("小强:12本")
    # jj.write("李明:15本")
    # jj.close()