错误文本写入到一个.txt文件在python

Question

我想提出一个方案，将 1.创建一个文本文件 2.允许密码存储 3.允许密码更改 4.添加附加密码 5.删除特定密码 问题出在def delete():。我在三条独立的线上输入了三个密码：第一，第二，第三。当我选择删除密码“秒”时，它重新打印之前的列表，然后在最后一个密码末尾打印新列表。

这里是我的代码：

import time 
def create(): 
    file = open("password.txt", "w") 
    passwordOfChoice = input("The password you want to store is: ") 
    file.write(passwordOfChoice) 
    print ("Your password is: ", passwordOfChoice) 
    file.close() 
    time.sleep(2) 
def view(): 
    file = open("password.txt","r") 
    print ("Your password is: ", 
      "\n", file.read()) 
    file.close() 
    time.sleep(2) 
def change(): 
    file = open("password.txt", "w") 
    newPassword = input("Please enter the updated password: ") 
    file.write(newPassword) 
    print ("Your new password is: ", newPassword) 
    file.close() 
    time.sleep(2) 
def add(): 
    file = open("password.txt", "a") 
    extraPassword = input("The password you want to add to storage is: ") 
    file.write("\n") 
    file.write(extraPassword) 
    print ("The password you just stored is: ", extraPassword) 
    file.close() 
    time.sleep(2) 
def delete(): 
    phrase = input("Enter a password you wish to remove: ") 

    f = open("password.txt", "r+") 
    lines = f.readlines() 

    for line in lines: 
     if line != phrase+"\n": 
      f.write(line) 
    f.close() 

print("Are you trying to: ", 
     "\n1. Create a password?", 
     "\n2. View a password?", 
     "\n3. Change a previous password?", 
     "\n4. Add a password?", 
     "\n5. Delete a password?", 
     "\n6. Exit?\n") 
function = input() 
print("") 

if (function == '1'): 
    create() 
elif (function == '2'): 
    view() 
elif (function == '3'): 
    change() 
elif (function == '4'): 
    add() 
elif (function == '5'): 
    delete() 
elif (function == '6'): 
    print("Understood.", "\nProgram shutting down.") 
    time.sleep(1) 
else: 
    print("Your answer was not valid.") 
    print("Program shutting down...") 
    time.sleep(1) 

为了证明我上面的意思，这里是我的输出：

Your password is: 
first 
second 
thirdfirst 
third 

可有人请告诉我如何解决我的def delete():功能，这样它会不重写原始数据？万分感谢！

Answer 1

问题出在'r +'模式。当您使用'r +'时，您可以读取和写入，当然，这取决于您在编写的文件中控制，其中。 发生什么事是你读取文件，光标停留在最后，所以当你写回文件时，Python尽职地将新的行放在文件的末尾。 有关文件方法，请参见the docs;你正在寻找像寻求。