title: how to insert numbers (i+1) in ndarray at the beginning?
body: <p>I have ndarray in npz file and I'm trying to insert numbers at index 0 and inserted numbers should be increase by 1.
  Below is my array</p>
  <pre><code>data = [[[3.56, 7.94, 1.78], [8.23, 1.25, 4.80], [0.51, 8.23, 5.67], [9.56, 7.94, 2.78], [5.23, 7.25, 0.80],...]]
  </code></pre>
  <p>And the resulted ndarray should like</p>
  <pre><code>data = [[[0, 3.56, 7.94, 1.78], [1, 8.23, 1.25, 4.80], [2, 0.51, 8.23, 5.67], [3, 9.56, 7.94, 2.78], [4, 5.23, 7.25, 0.80],...]]
  </code></pre>
  <p>I'm new in this field so I want some help to solve this problem.</p>
  <p>Moreover I tried <a href="https://stackoverflow.com/questions/36998260/prepend-element-to-numpy-array">this solution</a> but it is for 1D array.</p>
  <p>My sample code is</p>
  <pre><code>import numpy as np
  
  a = np.load('abc.npz')['data']
  b = a.insert(a, 0+1) # I'm confused here
  np.savez('new.npz', data=b)
  </code></pre>
  <p>Looking for some suggestions</p>