diy.py

# sb=open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","w",encoding="utf-8")
# sb.write("一giao我里giao\n")
# sb.close()
# sb=open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","a",encoding="utf-8")
# sb.write("一giao我里giao\n")
# sb.close()
abab=""
with open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","a",encoding="utf-8") as sb:
     sb.write("一gan我里gan\n")
with open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","r",encoding="utf-8") as sb:
    for data in sb:
        if "一gan我里gan\n" in data:
            data.replace("gan","gauauau")
        abab+=data   
with open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","w",encoding="utf-8") as sb:
    sb.write(abab)
with open(r"C:\Users\Administrator\Desktop\新建文本文档.txt","r",encoding="utf-8") as sb:
    a=sb.read()
    print(a)