title: How to connect Python arrays
body: <p>I  don't understand when it is sum operation or just connect two arrays</p>
  
  <pre><code>x = np.arange(10)
  x
  #array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
  
  x[4]=44
  x
  #array([ 0,  1,  2,  3, 44,  5,  6,  7,  8,  9])
  
  xs=np.split(x,5)
  xs
  #[array([0, 1]), array([2, 3]), array([44,  5]), array([6, 7]), array([8, 9])]
  </code></pre>
  
  <p>what is this shape  ?</p>
  
  <pre><code>xs=np.split(x,5)
  xs
  #[array([0, 1]), array([2, 3]), array([44,  5]), array([6, 7]), array([8, 9])]
  
  i=2
  xscn = np.concatenate((xs[:i]+xs[i+1:]))
  xscn
  #array([0, 1, 2, 3, 6, 7, 8, 9])
  </code></pre>
  
  <p>"so why it no summing the array just put them side side (not ariane grande ha ha ha"</p>
  
  <pre><code>f=(xs[:i]+xs[i+1:])
  f
  
  #[array([0, 1]), array([2, 3]), array([6, 7]), array([8, 9])]
  </code></pre>
  
  <p>so it just put one array after other.</p>
  
  <pre><code>cc=np.concatenate(f)   
  cc  
  #array([0, 1, 2, 3, 6, 7, 8, 9])
  
  ff=xs[:i]+xs[i+1:]
  ff
  #[array([0, 1]), array([2, 3]), array([6, 7]), array([8, 9])]
  </code></pre>
  
  <p>so when it adds and when it just sets one list after other also I can't type the shapes.</p>