Python：将多个2D列表附加到一个2D列表

为了简单起见，我将只使用两个列表。 因此，我有以下2D列表：

> > a = [[1,2,3],
> >      [1,2,3]]   
> > b = [[4,5,6],
> >      [4,5,6]]

如果我附加列表a和b，我希望得到以下结果：

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

[[1], [2], [3], [1], [2], [3], [None], 4, 5, 6, 4, 5, 6, [[None]]]

以下代码是我尝试过的：

filenames = [a,b]           #For the example, since I will have multiple arrays 
masterlist = [] 
counter = 0 
for file in filenames:
    if counter == 0:        #This if is to try to create lists within the list
        for row in file:    #This loops is to iterate throughout the whole list
                for col in row:
                    c = [masterlist.append([col])]
        [masterlist.append(c) for row, col in zip(masterlist, c)]
        counter = 1
    else:                   #This else is to append each element to their respective position
        for row in file:
                for col in row:
                    c = [masterlist.append(col)]
        [masterlist.append([c]) for row, col in zip(masterlist, c)]

打印主列表时的输出如下所示：

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

[[1], [2], [3], [1], [2], [3], [None], 4, 5, 6, 4, 5, 6, [[None]]]

---

我也不确定[没有]是从哪里来的。如我们所见，“4,5,6…”并没有分别添加到列表“[1]、[2]、[3]…”中。

您可以遍历列表中的项目，然后将它们添加到主列表中：

a = [[1,2,3],
     [1,2,3]]   
b = [[4,5,6],
     [4,5,6]]

masterlist = []

for aa,bb in zip(a,b):                 # loop over lists
    for itema, itemb in zip(aa,bb):    # loop over items in list
        masterlist = masterlist + [[itema, itemb]]

输出：

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

---

如果你使用numpy，这真的很容易

import numpy as np
a = np.array([[1,2,3],
     [1,2,3]])
    
b = np.array([[4,5,6],
     [4,5,6]])

fl = np.vstack(np.dstack((a,b)))

输出

array([[1, 4],
       [2, 5],
       [3, 6],
       [1, 4],
       [2, 5],
       [3, 6]])