Haskellで位置をリストにする
--位置をリストにする関数 --positions 1 [3, 2, 1, 3, 1]の値は[2, 4] positions :: Eq a => a -> [a] -> [Int] positions x xs = [j| (i, j) <- zip xs [0..n], i == x] where n = length xs - 1
--位置をリストにする関数 --positions 1 [3, 2, 1, 3, 1]の値は[2, 4] positions :: Eq a => a -> [a] -> [Int] positions x xs = [j| (i, j) <- zip xs [0..n], i == x] where n = length xs - 1