python实现嵌套列表平铺的两种方法

方法一：使用列表推导式 >>> vec = [[1,2,3],[4,5,6],[7,8,9]] >>> get = [num for elem in vec for num in elem] >>> get [1, 2, 3, 4, 5, 6, 7, 8, 9] 方法相当于 >>> vec = [[1,2,3],[4,5,6],[7,8,9]] >>> result = [] >>> for elem in vec: for num in elem: result.append(num) >>> result [1, 2, 3, 4, 5, 6, 7, 8, 9] 方法二： 使用sum