making new subarrays from two arrays with numpy

Question

I am learning numpy, and I need to figure out how to create a new numpy array from two defined numpy arrays, where the new array is effectively a bunch of subarrays created from the elements of array 1 being "mapped" to the elements of array 2.

What I mean is, that for:

array1 = [6,8,9]
array2 = [1, 2, 3]

then the resultant array needs to equal:

[[6,1], [6,2], [6,3], [8,1], [8,2], [8,3], [9,1], [9,2], [9,3]]

I would like to know how to do this with numpy-specific functions (so no 'for' loops for iterating over the array elements individually)

Dani Mesejo · Accepted Answer · 2021-10-29 17:31:21Z

1

Use np.meshgrid:

import numpy as np

array1 = [6, 8, 9]
array2 = [1, 2, 3]


def mesh(values):
    return np.array(np.meshgrid(*values)).T.reshape(-1, len(values))


res = mesh([array1, array2])
print(res)

Output

[[6 1]
 [6 2]
 [6 3]
 [8 1]
 [8 2]
 [8 3]
 [9 1]
 [9 2]
 [9 3]]

answered Oct 29, 2021 at 17:31

Dani Mesejo

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