Append an element to Array of Arrays

Suppose I have an array of arrays.

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

I want to add 10 as the first element of each of those arrays without running for loop. Result should look like

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

Plain append does not work.

np.append(10, x)  array([10,  1,  2,  3,  4,  5,  6])  

My original problem has 100K arrays. So I need to find an efficient way to do this.

https://stackoverflow.com/questions/67014535/append-an-element-to-array-of-arrays April 09, 2021 at 11:06AM