title: Replace "while" with "for" in given python script
body: <p>I have written following script in python which works fine:</p>
  
  <pre><code>from sys import argv
  
  script, filename = argv
  
  def brokerage(cost):
      vol = 100
      tamt = cost*vol
      br = (((cost*0.1)/100)*vol)*2
      rc = (0.0074*tamt)/100
      stt = (0.025*tamt)/100
      std = (0.004*tamt)/100
      stb = (11*br)/100
      tbr = br+rc+stt+std+stb
      return(tbr)
  
  cost1 = 10
  cost2 = 510
  
  while cost1 &lt; 501 and cost2 &lt; 1001:
      value1 = brokerage(cost1)
      value2 = brokerage(cost2)
      # Can't write 'float' to file so, changed it into string. Don't know why.
      x1 = str(value1)
      x2 = str(value2)
      line = "  |%d\t\t%s\t|\t|%d\t\t%s\t|" % (cost1, x1, cost2, x2)
      # use 'a' in 'open' function to append it, will not overwrite existing value
      # as with 'w'.
      save = open(filename, 'a')
      save.write(line)
      save.write("\n  |---------------------|\t|-----------------------|\n")
      save.close
      cost1+=10
      cost2+=10
  </code></pre>
  
  <p>Now instead of "while" I want to use "for" with minimal code structure change.</p>