title: python numpy array append not working in .py file, but works in terminal
body: <p>I am trying to append to a numpy array using np.append.</p>
  
  <p>For example,</p>
  
  <pre><code>a = np.array([1])
  
  np.append(a, [2])
  </code></pre>
  
  <p>this code works well in terminal (the result is array([1, 2])), but it won't work when I run a .py file including the same code included in it. When I print a after appending [2], it would still be [1].</p>
  
  <p>Here is the code for my test.py file:</p>
  
  <pre><code>import numpy as np
  
  a = np.array([1])
  print(a)
  np.append(a, [2])
  print(a)
  </code></pre>
  
  <p>and this is the result of running it with terminal:</p>
  
  <pre><code>python test.py
  [1]
  [1]
  </code></pre>
  
  <p>Wrong result with no error.
  Does anyone know what could possibly be the problem?</p>