我正在編寫一個Haskell函數,它接收一個字符串列表並返回一個包含前兩個字符串作爲結果的元組的列表。因此,一個例子輸出爲:包含列表中前兩個字符串作爲元組的返回列表
listtuple ["bride", "zilla", "crazy", "women"] = [("bride", "villa")]
listtuple ["basketball", "football"] = [("basketball", "football")]
我想接近它,像這樣的方式:
listtuple :: Eq a => [Str a] -> [(Str a, Str a)]
listtuple xs = [(x,y) | x <- xs !! 0, y <- xs !! 1]
基本上我計算過,我可以隨便挑中的第一和第二索引的元素該列表,但我收到錯誤。這裏有幫助嗎?