使用Python嵌套循环计算双倍余额递减折旧时计算错误求助

原代码在计算双倍余额递减折旧时存在多处逻辑和格式错误，导致输出不符合预期，以下是问题分析和修正方案：

原代码问题点 #

• 金额未格式化：缺少千分位分隔、未保留两位小数，不符合示例输出格式
• 年初价值逻辑颠倒：循环内先扣除折旧再输出年初价值，导致数值错误
• 累计折旧输出错误：循环中误将当年折旧额当作累计折旧输出
• 最后一年折旧未处理：未按规则将剩余账面价值全额计提折旧

修正后的代码 #

import locale

# 设置本地化格式，用于金额的千分位和小数处理
locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')

desc_of_item = input("Enter the description of the item: ")
yr_of_purchase = int(input("Enter the year of purchase: "))
cost = int(input("Enter the cost: $"))
estimated_life = int(input("Enter the estimated life (in years): "))
dep_method = int(input("""Enter the value corresponding to the depreciation method you want to use:
1. Straight-Line
2. Double-Declining Balance
Here: """))

if dep_method == 1:
    depreciation = (1 / estimated_life) * cost
    print(f"The depreciation of {desc_of_item} using the straight-line method is: ${depreciation:.2f}")
elif dep_method == 2:
    # 输出资产基本信息
    print(f"""Description: {desc_of_item}
Year of purchase: {yr_of_purchase}
Cost: {locale.currency(cost, grouping=True)}
Estimated life of item (years): {estimated_life}
Method of depreciation: Double-Declining Balance
""")
    
    current_value = cost
    total_depreciation = 0
    current_year = yr_of_purchase
    
    for year in range(estimated_life):
        # 输出年初价值
        print(f"Value at the beginning of {current_year}: {locale.currency(current_value, grouping=True)}")
        
        # 计算当年折旧额：最后一年全额计提剩余价值
        if year == estimated_life - 1:
            depreciation = current_value
        else:
            depreciation = (2 / estimated_life) * current_value
        
        # 更新累计折旧和当前价值
        total_depreciation += depreciation
        current_value -= depreciation
        
        # 输出当年折旧和累计折旧
        print(f"Amount of depreciation during {current_year}: {locale.currency(depreciation, grouping=True)}")
        print(f"Total depreciation during {current_year}: {locale.currency(total_depreciation, grouping=True)}")
        
        # 年份递增
        current_year += 1

修正说明 #

1. 金额格式化：引入locale模块实现金额的千分位分隔和两位小数显示，与示例输出格式一致
2. 逻辑顺序调整：先输出当年年初价值，再计算折旧，避免数值颠倒
3. 累计折旧修正：始终输出累计折旧的总和，而非当年折旧额
4. 最后一年处理：判断到最后一年时，直接将剩余账面价值作为折旧额，确保最终累计折旧等于资产成本

内容的提问来源于stack exchange，提问作者Mina Milad