将不同大小的numpy数组组合成一个更大的矩阵

Question

我想将不同大小的 numpy 数组的所有可能组合成一个更大的矩阵。例如 a = np.array([1, 2, 3, 4, 5]) , b = np.array([6, 7, 8]), c = np.array([9, 10, 3, 4, 5]) 输出应该是：

 array([[1., 6., 9.],
       [2., 7., 10.],
       [3., 8., 3.],
       [4., 6., 4.],
       [5., 7., 5.],
       [1., 8., 10.],
       [2., 6., 3.],
       [3., 7., 4.],
       [4., 8., 5.],
       [5., 6., 9.],
       .....
       [5., 8., 5.])

涵盖所有可能的组合。请注意，数组 b 值正在重复。我试过制作数组然后使用广播原理。

arr= np.ones((75,3))
arr[:,0]=arr[:,0]*a
arr[:,1]=arr[:,1]*b
arr[:,2]=arr[:,2]*c

但是获取操作数不能和形状一起广播。

（编辑）需要一个可以具有可变长度数组的动态数量的解决方案。不一定是三个数组。

Answer 1

您可以使用列表理解：

arr = np.array([[x,y,z] for x  in a for y in b for z in c])

Answer 2

我认为您正在寻找 meshgrid，它适用于任何个数组，现在只需将它们添加到参数中即可：

np.array(np.meshgrid(a,b,c)).T.reshape(-1,3)

如果你有一个数组列表：

l = [a,b,c]
np.array(np.meshgrid(*l)).T.reshape(-1,len(l))

输出：

array([[ 1,  6,  9],
       [ 1,  7,  9],
       [ 1,  8,  9],
       [ 2,  6,  9],
       [ 2,  7,  9],
       [ 2,  8,  9],
       [ 3,  6,  9],
       [ 3,  7,  9],
       [ 3,  8,  9],
       [ 4,  6,  9],
       [ 4,  7,  9],
       [ 4,  8,  9],
       [ 5,  6,  9],
       [ 5,  7,  9],
       [ 5,  8,  9],
       [ 1,  6, 10],
       [ 1,  7, 10],
       [ 1,  8, 10],
       [ 2,  6, 10],
       [ 2,  7, 10],
       [ 2,  8, 10],
       [ 3,  6, 10],
       [ 3,  7, 10],
       [ 3,  8, 10],
       [ 4,  6, 10],
       [ 4,  7, 10],
       [ 4,  8, 10],
       [ 5,  6, 10],
       [ 5,  7, 10],
       [ 5,  8, 10],
       [ 1,  6,  3],
       [ 1,  7,  3],
       [ 1,  8,  3],
       [ 2,  6,  3],
       [ 2,  7,  3],
       [ 2,  8,  3],
       [ 3,  6,  3],
       [ 3,  7,  3],
       [ 3,  8,  3],
       [ 4,  6,  3],
       [ 4,  7,  3],
       [ 4,  8,  3],
       [ 5,  6,  3],
       [ 5,  7,  3],
       [ 5,  8,  3],
       [ 1,  6,  4],
       [ 1,  7,  4],
       [ 1,  8,  4],
       [ 2,  6,  4],
       [ 2,  7,  4],
       [ 2,  8,  4],
       [ 3,  6,  4],
       [ 3,  7,  4],
       [ 3,  8,  4],
       [ 4,  6,  4],
       [ 4,  7,  4],
       [ 4,  8,  4],
       [ 5,  6,  4],
       [ 5,  7,  4],
       [ 5,  8,  4],
       [ 1,  6,  5],
       [ 1,  7,  5],
       [ 1,  8,  5],
       [ 2,  6,  5],
       [ 2,  7,  5],
       [ 2,  8,  5],
       [ 3,  6,  5],
       [ 3,  7,  5],
       [ 3,  8,  5],
       [ 4,  6,  5],
       [ 4,  7,  5],
       [ 4,  8,  5],
       [ 5,  6,  5],
       [ 5,  7,  5],
       [ 5,  8,  5]])

将不同大小的numpy数组组合成一个更大的矩阵

Combine numpy arrays of different sizes into a bigger matrix

python

arrays

numpy

array-broadcasting