Renaming column names of a DataFrame in Spark Scala

Question

I am trying to convert all the headers / column names of a DataFrame in Spark-Scala. as of now I come up with following code which only replaces a single colum

Answer 1

tow table join not rename the joined key

// method 1: create a new DF
day1 = day1.toDF(day1.columns.map(x => if (x.equals(key)) x else s"${x}_d1"): _*)

// method 2: use withColumnRenamed
for ((x, y) <- day1.columns.filter(!_.equals(key)).map(x => (x, s"${x}_d1"))) {
    day1 = day1.withColumnRenamed(x, y)
}

works!