How to convert a SQLContext Dataframe to RDD of vectors in Python?
The Dataframe Python API exposes the RDD of a Dataframe by calling the following :

df.rdd # you can save it, perform transformations of course, etc. 


df.rdd returns the content as an pyspark.RDD of Row.

You can then map on that RDD of Row transforming every Row into a numpy vector. I can't be more specific about the transformation since I don't know what your vector represents with the information given. 

Note 1: dfis the variable define our Dataframe. 

Note 2: this function is available since Spark 1.3