如何拆分自定义数据类型的元素

Question

我是Haskell的新手。

我对自定义数据类型很困惑

所以我要做的是显示一个人的总年龄以及每个人的姓名和年龄

所以我希望它看起来像这样

Detail "Ben" 20 Student
       "Joy" 25 Police
       "Hellen" 10 Student
Total   55 -- 20 + 25 + 10 

这是我的代码

 data Person = Name String Int Job deriving Show -- name age Job
 data Det = Total Int | Detail String Int Job deriving Show -- age | name age Job
 data Job = Police | Student deriving Show 


Split :: Person -> Int -- Need to get eacn age to accumulate one another for total age 
Split (Name _ age _ ) = age

check1 :: [Person] -> Det -- Need to sum all the age with Split function 
......?

Answer 1

total :: [Person] -> Int
total [] = 0
total (x:xs) = getAge x where
      getAge (Name _ age _ ) = age + total xs

您需要使用“人员”类型的列表。这将返回列表中所有元素的总寿命。