scala - Replace null values in Spark DataFrame

Question

I saw a solution here but when I tried it doesn't work for me.

First I import a cars.csv file :

val df = sqlContext.read
              .format("com.databricks.spark.csv")
              .option("header", "true")
              .load("/usr/local/spark/cars.csv")

Which looks like the following :

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

Then I do this :

df.na.fill("e",Seq("blank"))

But the null values didn't change.

Can anyone help me ?

Answer 1

This is basically very simple. You'll need to create a new DataFrame. I'm using the DataFrame df that you have defined earlier.

val newDf = df.na.fill("e",Seq("blank"))

DataFrames are immutable structures. Each time you perform a transformation which you need to store, you'll need to affect the transformed DataFrame to a new value.