title: Python list assignment index out of range
body: <p>I keep getting an IndexError: list assignment index out of range.
  Here is my code:</p>
  
  <pre><code>import numpy as np
  import asciidata
  
  fv = [] 
  fb = []
  data = asciidata.open('Flux.txt')
  for i in data[1]:
      fv.append(float(i))
  for i in data[2]:
      fb.append(float(i))
  
  mv = []
  mb = []
  for i in range (0,25):
      mv[i] = 10.1 - 2.5 * np.log(fv[i]/1220000)
      mb[i] = 11.0 - 2.5 * np.log(fb[i]/339368)
      print i, mv[i], mb[i]
  </code></pre>