python - 如何在python中创建新列表

Question

我想从一个列表创建新列表。这是我正在处理的示例列表：

matrixlist = [['Matrix', '1'], ['1', '4', '6'], ['5', '2', '9'], ['Matrix', '2'], ['2', '6'], ['1', '3'], ['8', '6'], ['Matrix', '3'], ['5', '6', '7', '9'], ['1', '4', '2', '3'], ['8', '7', '3', '5'], ['9', '4', '5', '3'], ['Matrix', '4'], ['7', '8'], ['4', '6'], ['2', '3']]

我用 for 循环这样拆分它们：

matrix1 = [['1', '4', '6'], ['5', '2', '9']]
matrix2 = [['2', '6'], ['1', '3'], ['8', '6']]
matrix3 = [['5', '6', '7', '9'], ['1', '4', '2', '3'], ['8', '7', '3', '5'], ['9', '4', '5', '3']]
matrix4 = [['7', '8'], ['4', '6'], ['2', '3']]

但是我想将长列表提供给程序，它会创建列表并在其中附加相关元素。就像 matrix1 列表中的矩阵 1 元素一样。

编辑：我不能使用任何高级内置功能。我只能在代码中使用简单的（如追加、弹出、反向、范围）和我的函数。

标签： pythonpython-3.xlistfunction

Answer 1

您可以使用itertools.groupby：

from itertools import groupby
matrixlist = [['Matrix', '1'], ['1', '4', '6'], ['5', '2', '9'], ['Matrix', '2'], ['2', '6'], ['1', '3'], ['8', '6'], ['Matrix', '3'], ['5', '6', '7', '9'], ['1', '4', '2', '3'], ['8', '7', '3', '5'], ['9', '4', '5', '3'], ['Matrix', '4'], ['7', '8'], ['4', '6'], ['2', '3']]
result = [list(b) for a, b in groupby(matrixlist, key=lambda x:x[0] == 'Matrix') if not a]

输出：

[[['1', '4', '6'], ['5', '2', '9']], 
 [['2', '6'], ['1', '3'], ['8', '6']], 
 [['5', '6', '7', '9'], ['1', '4', '2', '3'], ['8', '7', '3', '5'], ['9', '4', '5', '3']], 
 [['7', '8'], ['4', '6'], ['2', '3']]]