Python整数输入字典映射转换的代码问题排查与修复

• 代码未提前定义year变量就直接做条件判断，运行时会直接抛出NameError中断，缺少接收用户年级确认输入的步骤。
• subjectConversions字典的所有键都是字符串格式（如"1"、"2"），但代码将用户输入转换为int整数类型，用整数作为键查询字典时会触发KeyError，无法匹配到对应科目名称。
• 选项提示文本存在拼写错误：Desingn & Technology正确拼写为Design & Technology。
• 结果字符串拼接时"You have selected"末尾缺少空格，输出时会出现文字和科目名粘连的格式问题。

# 新增年级确认输入逻辑
year = input("请确认你为9年级学生，输入y确认：").strip().lower()

subjectConversions = {
  "1": "Computer science",
  "2": "Geography",
  "3": "History",
  "4": "French",
  "5": "Drama",
  "6": "Music",
  "7": "Art",
  "8": "Design & Technology",
  "9": "Physical Education",
  "10": "Cooking",
  "11": "Business studies",
}

if year != "y":
  print("Sorry! Year 9 only!")
  quit()
else:
  print("Welcome!")

# 修正选项文本拼写错误
print("Take a look at the list below for GCSE subjects. Once that is done, select four different options at each prompt.\nComputer Science [1], Geography [2], History [3], French [4], Drama [5], Music [6], Art [7], Design & Technology [8], Physical Education [9], Cooking [10], Business studies [11]\n")
# 保留输入为字符串类型，和字典键类型匹配，同时去除输入首尾空白字符
Op1 = input("Option one: ").strip()

# 新增输入合法性校验，避免无效输入导致崩溃
if Op1 not in subjectConversions:
  print("无效选项，请输入1-11之间的序号")
  quit()

# 补全拼接处的空格
print("You have selected " + subjectConversions[Op1] + ", is that correct? [y/n]")

后续如果要完成4个科目选择的逻辑，重复对应输入、校验、取值的步骤即可，注意判断用户是否选了重复科目。

内容的提问来源于stack exchange，提问作者Jogaly Syndrone