title: Pyspark RDD: convert to string
body: <p>Using <code>rddfloat = rdd.map( (float(x[0]), float(x[1])) )</code>, I converted the columns of an rdd into floats so that I could do math with them. Now I'm finished with the math and I want to convert them back into their original StringType.</p>
  
  <p>I've tried rddstr = rddfloat( (str(x[0]), str(x[1]), str(x[2])) ), and it does return a string <code>'40.745555'</code>, but that's not the same as the original rdd <code>u'40.745555'</code>. What is the difference between these, and how can I convert it back to how it was originally?</p>