title: Indexing array from second element for all elements
body: <p>I think it must be easy, but I cannot google it. Suppose I have array of numbers 1, 2, 3, 4.</p>
  
  <pre><code>import numpy as np
  
  a = np.array([1,2,3,4])
  </code></pre>
  
  <p>How to index array if I want sequence 2, 3, 4, 1?? 
  I know that for sequence 2, 3, 4 I can choose e.g.:</p>
  
  <pre><code>print(a[1::1])
  </code></pre>