title: String replace in Spark RDD
body: <p>I will explain the problem first mentioning the code.</p>
  
  <pre><code>numPartitions = 2
  rawData1 = sc.textFile('train_new.csv', numPartitions,use_unicode=False)
  
  
  rawData1.take(1)
  
  ['1,0,0,0,0,0,0,0,0,0,0,1,0,0,5,0,0,0,0,0,0,0,0,0,3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,2,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,9,0,0,0,0,0,Class_2']
  </code></pre>
  
  <p>Now i want to replace  <strong>Class_2</strong>   to <code>2</code></p>
  
  <p>after replacement answer should be</p>
  
  <pre><code>['1,0,0,0,0,0,0,0,0,0,0,1,0,0,5,0,0,0,0,0,0,0,0,0,3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,2,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,9,0,0,0,0,0,2']
  </code></pre>
  
  <p>Once i get it for this row, i will perform the operation for the whole data set</p>
  
  <p>Thanks in Advance
  Aashish</p>