title: String Replace in csv
body: <p>Below, I am trying to replace data in a csv. The code works, but it replaces anything matching <code>stocklevel</code>in the file.</p>
  
  <pre><code>def updatestocklevel(quantity, stocklevel, code):
      newlevel = stocklevel - quantity
      stocklevel = str(stocklevel)
      newlevel = str(newlevel)
      s = open("stockcontrol.csv").read()
      s = s.replace (stocklevel ,newlevel) #be careful - will currently replace any number in the file matching stock level!
      f = open("stockcontrol.csv", 'w')
      f.write(s)
      f.close()
  </code></pre>
  
  <p>My csv looks like this;</p>
  
  <pre><code>34512340,1
  12395675,2
  56756777,1
  90673412,2
  12568673,3
  22593672,5
  65593691,4
  98593217,2
  98693214,2
  98693399,5
  11813651,85
  98456390,8
  98555567,3
  98555550,45
  98553655,2
  96553657,1
  91823656,2
  99823658,2
  </code></pre>
  
  <p>Elsewhere in my program, I have a function that searches for the code (8 digits)
  Is it possible to say, if the <code>code</code> is in the line of the csv, replace the data in the second column? (data[2])</p>