Python嵌套字典赋值异常：旧数据被覆盖问题咨询

你的问题核心在于Python中字典是可变对象，赋值操作传递的是对象引用而非副本：

• 你在循环外初始化了bidder_details字典，每次循环只是修改它的键值对，而非创建新字典。
• bidders[ID] = bidder_details这行代码并没有把字典的内容存进去，而是把这个字典的引用存入了bidders。因此所有ID对应的都是同一个字典对象，最后一次循环的赋值会覆盖所有引用指向的内容。

解决方法1：循环内新建字典（推荐） #

每次循环创建一个全新的bidder_details字典，从根源避免引用复用：

# Initializing dictionaries
bidders = {}

# Loop for storing bidders details
new_entry = "yes"
ID = 0
while new_entry.lower() == "yes":
    name = input("What is your name?: ")
    amount = float(input("What's your bid?: "))
    ID += 1
    # 每次循环新建字典，存储当前竞价者的信息
    bidder_details = {
        "bidder_name": name,
        "bid_amount": amount
    }

    bidders[ID] = bidder_details

    new_entry = input("Are there any other bidders? Type 'yes' or 'no'\n").lower()
    if new_entry not in ("no", "yes"):
        print("\nIncorrect input! Taking no new bidders.")
        new_entry = "no"


print(f"\n{bidders}")

解决方法2：存储字典副本 #

如果需要复用外部字典，每次存储时使用copy()方法创建浅拷贝（当前场景下字典值都是不可变类型，浅拷贝足够）：

# Initializing dictionaries
bidder_details = {}
bidders = {}

# Loop for storing bidders details
new_entry = "yes"
ID = 0
while new_entry.lower() == "yes":
    name = input("What is your name?: ")
    amount = float(input("What's your bid?: "))
    ID += 1
    # 更新原字典内容
    bidder_details["bidder_name"] = name
    bidder_details["bid_amount"] = amount

    # 存储字典副本，而非原字典引用
    bidders[ID] = bidder_details.copy()

    new_entry = input("Are there any other bidders? Type 'yes' or 'no'\n").lower()
    if new_entry not in ("no", "yes"):
        print("\nIncorrect input! Taking no new bidders.")
        new_entry = "no"


print(f"\n{bidders}")

内容的提问来源于stack exchange，提问作者Vaibhav Singh