let rec filtersList2fromList1 (List1:string list) (List2:string list) : string list =
let finalList = [] in
match List1 with
| s :: tl -> if List.mem s List2 = true
then finalList @ [s] else filtersList2fromList1 tl List2
| [] -> []
,這樣,我想要做的兩件事情後,「然後」聲明在「如果..然後..否則」語句
filtersList2fromList1 ["x";"y";"z"] ["z";"x"] would be ["x";"z"]
filtersList2fromList1 ["x";"y";"z"] ["x"] would be ["x"]
我想,如果補充的是,是什麼「if」語句爲真,不僅會執行「finalList @ [s]」,還會執行「filtersList2fromList1 tl List2」,這樣它將成爲遞歸。在沒有執行「filtersList2fromList1 tl List2」的情況下,
filtersList2fromList1 ["x";"y";"z"] ["z";"x"]
只會是["x"]
,這是錯誤的。
我應該如何解決這個問題?
非常感謝您
什麼是dolls_of的定義是什麼? – 2011-01-14 21:15:34