title: How to put Python loop output in a list
body: <p>As a beginner to Python(SAGE) I want to put the output of this for loop 
  into a list:</p>
  
  <pre><code>for y in [0,8] : 
     for z in [0,1,2,3] :
       x=y+z
  
       print x
  </code></pre>
  
  <p>The output is </p>
  
  <pre><code>0
  1
  2
  3
  8
  9
  10
  11
  </code></pre>
  
  <p>(vertically). I want a list so I can use it for a later operation:
  I want [1,2,3,8,9,10,11].
  I found a similar question and I realize that the output is recalculated
  each time. Is there a simple way to store them in a list? Following a suggestion for the other answer, I tried "append" like this, but it gives an error message:</p>
  
  <pre><code>x=[]
  for y in [0,2*3] : 
   for z in [0,1,2,3] :
     x=y+z
     x.append(x)
  
    print x
  </code></pre>