如何在haskell列表中将元素与其索引相关联

Question

给定一个列表[[1],[3,5],[],[1,9],[3,5],[9,7],[1,9]],我如何将它与元素索引相关联[(0,[1]), (1,[3,5]), (2,[]), (3,[1,9]), (4,[3,5]), (5,[9,7]), (6,[1,9])]

Answer 1

你可以使用zip

zip [0..] theList

例如

zip [0..] [[1],[3,5],[],[1,9],[3,5],[9,7],[1,9]]

产量

[(0,[1]), (1,[3,5]), (2,[]), (3,[1,9]), (4,[3,5]), (5,[9,7]), (6,[1,9])]