我的問題是我有一個串列，想洗掉其中的一些字串。但是當我第一次洗掉時就可以了。但第二次，它洗掉了字串但帶回了第一個。你知道我怎樣才能避免這種情況嗎？謝謝
Prelude Data.List Data.Char> x = ["ab","cd","ef","gh"]
Prelude Data.List Data.Char> delete "ab" x
["cd","ef","gh"]
Prelude Data.List Data.Char> delete "cd" x
["ab","ef","gh"]
!!這里"ab"回來了，我不想要這個！謝謝
uj5u.com熱心網友回復：
請參閱此處的“如何“思考功能性” ” 。總之，是一樣的；回傳新值，它不會改變現有的.xxdelete "abc" xx
如果要參考這個新值，請給它一個新名稱，如下所示：
> x = ["ab","cd","ef","gh"]
> x2 = delete "ab" x
> delete "cd" x2
["ef","gh"]
轉載請註明出處，本文鏈接：https://www.uj5u.com/shujuku/427254.html