Python类vlookup的finder函数如何补充未匹配返回Not Found逻辑

修改说明 #

你需要新增未命中匹配的判断逻辑，具体改动如下：

1. 遍历前新增匹配状态标记变量，默认值为未找到
2. 匹配成功时更新状态标记，同时可加break终止后续无效遍历
3. 遍历结束后判断状态，未匹配则输出"Not found"

新增代码片段 #

• 遍历前新增：found = False
• 匹配成功的逻辑块内新增：

  found = True
  break # 找到匹配后直接结束遍历，优化执行效率
  

• 遍历结束后新增：

  if not found:
      print("Not found")
  

修改后的完整代码 #

def finder(lookupvalue, lookuplist, col_index):
    user_list = [
        ["Account number","Currency","Balance"],
        ["001-987654-003","USD",1300.72],
        ["001-919202-100","EUR",105.01],
        ["001-905700-100","EUR",305.00],
        ["001-908415-307","CHF",20804.98],
        ["011-974777-200","PLN",208.15],
        ["001-931654-001","USD",450.7]
    ]

    errormsg = 'Out of range'
    if col_index > 3:
        raise ValueError(errormsg)
    
    found = False
    for row in user_list:
        if row[0] == lookupvalue:
            print(row[col_index-1])
            found = True
            break
    
    if not found:
        print("Not found")

额外优化建议 #

当前函数参数lookuplist没有被实际使用，内部硬编码了user_list。如果需要支持传入自定义查找列表，可以删除函数内部的user_list定义，遍历逻辑直接使用传入的lookuplist参数即可。

内容的提问来源于stack exchange，提问作者pucktack