title: Add RDD to DataFrame Column PySpark
body: <p>I want to create a Dataframe with the columns of two RDD's. 
  The first is RDD that i get from CSV and second is another RDD with a cluster prediction of each row.</p>
  
  <p>My schema is:</p>
  
  <pre><code>customSchema = StructType([ \
  StructField("Area", FloatType(), True), \
  StructField("Perimeter", FloatType(), True), \
  StructField("Compactness", FloatType(), True), \
  StructField("Lenght", FloatType(), True), \
  StructField("Width", FloatType(), True), \
  StructField("Asymmetry", FloatType(), True), \
  StructField("KernelGroove", FloatType(), True)])
  </code></pre>
  
  <p>Map my rdd and create the DataFrame:</p>
  
  <pre><code>FN2 = rdd.map(lambda x: (float(x[0]), float(x[1]),float(x[2]),float(x[3]),float(x[4]),float(x[5]),float(x[6])))
   df = sqlContext.createDataFrame(FN2, customSchema)
  </code></pre>
  
  <p>And my cluster prediction:</p>
  
  <pre><code>result = Kmodel.predict(rdd)
  </code></pre>
  
  <p>So, to conclude i want to have in my DataFrame the rows of my CSV and their cluster prediction at the end.</p>
  
  <p>I tried to add a new column with .WithColumn() but i got nothing.</p>
  
  <p>Thanks.</p>