用字典中的新值替换键值对中的空白值（python 3.x）

Question

我需要创建一个字典来存储任意数量的用户名和密码对，但我不知道如何用新密码替换空白值。不幸的是，我必须先完成用户名输入，然后才能要求输入密码。

dictionary= {}   # blank database
userpassno = int(input("How many username and password pairs?"))    # user input for amount of pairs
for i in range(userpassno):     # loop that runs as many times as the number of pairs
    username = input("Enter username:")     # Username input
    database[username] = None               # No passwords yet
for i in range(userpassno):
    password = input("Enter password:")  # password input
    database[username] = password        # Puts passwords into database
print(database)

Answer 1

您可以使用一个列表来存储用户在第一个循环中输入的所有用户名，然后在第二个循环中使用存储的用户名将密码输入分配给dict中的相应条目：

database= {}   # blank database
userpassno = int(input("How many username and password pairs?"))    # user input for amount of pairs
usernames = []
for i in range(userpassno):     # loop that runs as many times as the number of pairs
    usernames.append(input("Enter username:"))     # Username input
for username in usernames:
    database[username] = input("Enter password:")  # password input
print(database)