问如何在不使用numpy的情况下将(1D)平面列表重塑为列表数组的2D列表？

EN

def group_size(L,size):
    return list(zip(*[iter(L)]*size))

print(group_size([1,2,3,4,5,6,7,8,9],3))

def reshape_list(L, xsize, ysize=None, fillna=False):
    if isinstance(L[0], list):
        _L = [] 
        for l in L: _L+=l
        L = _L 
    if not fillna: 
        if ysize:
            assert xsize*ysize == len(L)
        else: 
            assert len(L)%xsize == 0
        return list(map(list,zip(*[iter(L)]*xsize)))
    else: 
        gap = []
        if ysize:
            if xsize*ysize > len(L): 
                gap = [None]*(xsize*ysize - len(L))
        else: 
            v, r = divmod(len(L),xsize)
            gap = [None]*r
        return list(map(list, zip(*[iter(L+gap)]*xsize)))

print(reshape_list([1,2,3,4,5,6], 2)) 
print(reshape_list([[1,2],[3,4],[5,6]], 3))

[[1, 2], [3, 4], [5, 6]]
[[1, 2, 3], [4, 5, 6]]

def transpose_2D_list(L):
    return list(map(list,zip(*L)))

print(transpose_2D_list([[1,2],[3,4],[5,6]]))

[[1, 3, 5], [2, 4, 6]]