Converting RDD to spark data frames in python and then accessing a particular values of columns
To read a csv file to spark dataframe you should use spark-csv. 
https://github.com/databricks/spark-csv

df = sqlContext.read.format('com.databricks.spark.csv').options(header='true', inferschema='true').load('cars.csv')


How to use spark csv
If you are using pyspark directly from the terminal. Instead of calling 

$SPARKHOME/bin/pyspark


You have to use

$SPARKHOME/bin/pyspark --packages com.databricks:spark-csv_2.11:1.4.0 


and then use the code above. 

If you are using ipython + findspark, you'll have to modify your PYSPARK_SUBMIT_ARGS (before starting ipython)

export PYSPARK_SUBMIT_ARGS=--master local[4] --packages "com.databricks:spark-csv_2.11:1.4.0" pyspark-shell