apache spark - Scala: How can I replace value in Dataframes using scala

Question

For example I want to replace all numbers equal to 0.2 in a column to 0. How can I do that in Scala? Thanks

Edit:

|year| make|model| comment            |blank|
|2012|Tesla| S   | No comment         |     | 
|1997| Ford| E350|Go get one now th...|     | 
|2015|Chevy| Volt| null               | null| 

This is my Dataframe I'm trying to change Tesla in make column to S

Answer 1

Spark 1.6.2, Java code (sorry), this will change every instance of Tesla to S for the entire dataframe without passing through an RDD:

dataframe.withColumn("make", when(col("make").equalTo("Tesla"), "S")
                             .otherwise(col("make") 
                    );

Edited to add @marshall245 "otherwise" to ensure non-Tesla columns aren't converted to NULL.