Ramesh Ramesh - 9 days ago 14
Scala Question

Dropping multiple columns from Spark dataframe by Iterating through the columns from a Scala List of Column names

I have a dataframe which has columns around 400, I want to drop 100 columns as per my requirement.
So i have created a Scala List of 100 column names.
And then i want to iterate through a for loop to actually drop the column in each for loop iteration.

Below is the code.

final val dropList: List[String] = List("Col1","Col2",...."Col100”)

def drpColsfunc(inputDF: DataFrame): DataFrame = {
for (i <- 0 to dropList.length - 1) {
val returnDF = inputDF.drop(dropList(i))
}
return returnDF
}

val test_df = drpColsfunc(input_dataframe)

test_df.show(5)

Answer

Answer:

val colsToRemove = Seq("colA", "colB", "colC", etc) 

val filteredDF = df.select(df.columns .filter(colName => !colsToRemove.contains(colName)) .map(colName => new Column(colName)): _*)