从可区分联合中的记录访问数据

Question

有了这个设置，我如何遍历列表并打印每个员工的数据？

type Person =
    { first_name: string
      last_name: string
      age: int
      salary_hour: int }

type Employee =
    | Administrator of Person
    | OfficeWorker of Person
    | WarehouseWorker of Person


let emps =
    [ Administrator
        { first_name = "name"
          last_name = "name"
          age = 19
          salary_hour = 200 }]

Answer 1

通常，我建议将其分解。

从每个部分的函数开始，例如打印每个人的函数（或转换为字符串，这通常更容易重用和组合），然后是第二个函数，使用该函数将员工转换为字符串.

最后，您可以使用 List.iter 迭代您的列表以打印：

let personToString p =
    sprintf "%s %s [%d] - Salary %d" p.first_name p.last_name p.age p.salary_hour
    
let employeeToString e =
    match e with
    | Administrator a -> sprintf "Administrator: %s" (personToString a)
    | OfficeWorker o -> sprintf "Office: %s" (personToString o)
    | WarehouseWorker w -> sprintf "Warehouse: %s" (personToString w)
    
emps |> List.iter (fun e -> employeeToString e |> printfn "%s")

从可区分联合中的记录访问数据

access data from a record in a discriminated union

f#

list

record

discriminated-union