title: After copying file, can't properly use len(var_name) to get the size of copied file?
body: <p>I'm working through Learn Python The Hard Way and am curious why I can't check the size of the file that I have copied to. </p>
  
  <p>Here is the amended script that I added to from the book. </p>
  
  <pre><code>from sys import argv
  from os.path import exists
  
  script, from_file, to_file = argv
  
  print "Copying from %s to %s" % (from_file, to_file)
  
  # We could do these two lines of code in one line, how?
  in_file = open(from_file)
  in_data = in_file.read()
  
  print "The input file is %d bytes long\n\n" % len(in_data)
  
  print "Does the output file exist? %r \n\n" % exists(to_file)
  
  print "Ready, hit RETURN to continue, CTRL-C to abort.\n"
  raw_input()
  
  out_file = open(to_file, 'w')
  out_file.write(in_data)
  out_file2 = open(to_file) # Added this line
  out_data = out_file2.read() # Added this line
  
  
  print "Completed. The copied file is %r bytes long." % len(out_data)
  
  in_file.close()
  </code></pre>
  
  <p>Thanks</p>