python - 如何从数组数组中创建一个 numpy 数组？

Question

我正在 ipython3 中进行试验，我在其中创建了一个数组数组:

In [105]: counts_array
Out[105]: 
array([array([ 17,  59, 320, ...,   1,   7,   0], dtype=uint32),
       array([ 30,  71, 390, ...,  12,  20,   6], dtype=uint32),
       array([  7, 145, 214, ...,   4,  12,   0], dtype=uint32),
       array([ 23, 346, 381, ...,  15,  19,   5], dtype=uint32),
       array([ 51,  78, 270, ...,   3,   0,   2], dtype=uint32),
       array([212, 149, 511, ...,  19,  31,   8], dtype=uint32)], dtype=object)

In [106]: counts_array.shape
Out[106]: (6,)

In [107]: counts_array[0].shape
Out[107]: (1590,)

我想从我创建的这个怪物中获得一个普通的 shape=(6, 1590), dtype=uint32 数组。

我该怎么做？

Answer 1

您可以使用 np.vstack -

np.vstack(counts_array)

另一种方式 np.concatenate -

np.concatenate(counts_array).reshape(len(counts_array),-1)

sample 运行-

In [23]: a
Out[23]: 
array([array([68, 92, 84, 35, 14, 71, 55, 40, 21, 41]),
       array([30, 90, 52, 64, 86, 68, 61, 85, 26, 98]),
       array([98, 64, 23, 49, 13, 17, 52, 96, 97, 19]),
       array([54, 26, 25, 22, 95, 77, 20, 73, 22, 80]),
       array([15, 84, 91, 54, 25, 21, 37, 19, 25, 25]),
       array([87, 17, 49, 74, 11, 34, 27, 23, 22, 83])], dtype=object)

In [24]: np.vstack(a)
Out[24]: 
array([[68, 92, 84, 35, 14, 71, 55, 40, 21, 41],
       [30, 90, 52, 64, 86, 68, 61, 85, 26, 98],
       [98, 64, 23, 49, 13, 17, 52, 96, 97, 19],
       [54, 26, 25, 22, 95, 77, 20, 73, 22, 80],
       [15, 84, 91, 54, 25, 21, 37, 19, 25, 25],
       [87, 17, 49, 74, 11, 34, 27, 23, 22, 83]])