numpy.concatenate如何在列表上工作

Question

我试图弄清楚为什么以下代码不起作用：

import numpy as np

failList = [[[1], [2]],

           [[3, 4, 5, 6], [7]],

           [[8], [9]],

           [[10], [11, 12]],

           [[13], [14, 15, 16]]]

goodList = [[[1], [2], [3, 4, 5, 6], [7], [8]],

           [[9], [10], [11, 12], [13], [14, 15, 16]]]

goodList2 = [[[1], [2], [3, 4, 5, 6], [7], [8]],

            [[9], [10], [11, 12], [13], [14, 15, 16]],

            [[9], [10], [11, 12], [13], [14, 15, 16]]]

myLists = [failList, goodList, goodList]

for l in myLists:

    print([len(l[i]) for i in range(len(l))])

    print([len(l[i][j]) for i in range(len(l)) for j in range(len(l[i]))])

    try:

        np.concatenate(l)

        print("worked")

    except:

        print("failed")

输出为：

[2, 2, 2, 2, 2]

[1, 1, 4, 1, 1, 1, 1, 2, 1, 3]

failed

[5, 5]

[1, 1, 4, 1, 1, 1, 1, 2, 1, 3]

worked

[5, 5, 5]

[1, 1, 4, 1, 1, 1, 1, 2, 1, 3, 1, 1, 2, 1, 3]

worked

有人可以解释一下，为什么第一个列表不能被串联，而其他人可以吗？