无法编写条件以更新python

问题描述

请帮助！如何在现有代码中编写条件，将进行如下检查。请看注释块。我无法在字典/列表中附加值。我需要写/更改什么？

当用户返回主菜单并再次使用相同的密钥文件运行加密过程，但将加密的文件保存为其他名称。用户可以使用同一密钥创建尽可能多的加密文件。

我的尝试：

import Encrypt
from collections import defaultdict

key_value_dict = {}

def encrypt_file():
    try:

        txtfile = input("Your plain txt file that you want to encrypt : ")
        encrypt_file = input("Directory to save the encrypted file : ")
        key = input("Key for encryption : ")

        # process for encryption
        Encrypt.encrypt_file(txtfile,encrypt_file,key)

        # ----------------------------------------------------------------
        key_value_dict = defaultdict(list,{key: encrypt_file})

        print(key_value_dict)

        key_value_dict [key].append(encrypt_file)
        print(key_value_dict )
        # --------------------------------------------------------------------
    except FileNotFoundError:
        print("File Not Found!")


def menu():
    selection = True
    while selection:
        print("""
MAIN MENU:
[1] Encrypt files using existing keys.
[2] Exit.
        """)
        try:  
            selection = input("Please select : ")

            if selection == "1":
                encrypt_file()  # call function
            elif selection == "2":
                print("\n[4] Keys are used for encryption:","\n",key_value_dict)
                selection = None
            else:
                print("\n Invalid selection! Try again")
        except ValueError:  
            print("\n Exception: Invalid user input!")

# Main function
if __name__ == '__main__':
    menu()

解决方法

如果我理解正确，我认为您不需要defaultdict

尝试一下：

# define this first outside the function like you have
encrypt_key_value_dict = {}

# Within your code block,get rid of the assignment to default dict
if encrypt_key_value_dict[key]:
    encrypt_key_value_dict.append(encrypt_file)
else:
    encrypt_key_value_dict[key] = [encrypt_file]

我无法从您的代码中看到您的密钥在哪里被传递等等，但是我确定您可以弄清楚。

append dictionary list python updates