title: Python scoping mutable vs immutable
body: <p>First I'm going to start like everyone else. I'm new to python. My teacher gave me the problem:</p>
  
  <pre><code>def f(a, b, c):  
      a    = 1 
      c    = b 
      c[0] = 2 
  a = 10 
  b = [11, 12, 13] 
  c = [13, 14, 15] 
  f(a, b, c) 
  print a, b, c
  </code></pre>
  
  <p>It prints:</p>
  
  <pre><code>10 [2, 12, 13] [13, 14, 15]
  </code></pre>
  
  <p>I understand that a stays at 10 because integers are immutable, but I don't understand why b changes and c doesn't.</p>