我了,我想通過我的客戶名單迭代找到正確的客戶,當我發現他們,我想要展示的任何非零INT的附加到他們。我不知道如何繼續。我知道店裏只有一個人的姓名記錄。基本哈斯克爾:列表理解
type Name = String
type Customer = (Name,Int,Int)
type Shop = [Customer]
shop = [cust1, cust2]
cust1 = ("Steve", 321, 123) :: Customer
cust2 = ("John", 0,678) :: Customer
getName :: Customer -> Name
getName (a, b,c) = a
getNumbers :: Customer -> [Int]
getNumbers (a,b,c) = filter (/=0) [b,c]
rental:: Shop-> Name -> [Int]
rental shop' name' = map getNumbers [ x|x<-shop',getName x == name']
一如既往的完美謝謝! – John