text1        text2

text1 text2

import org.apache.spark.sql.functions._

val myUDf = udf((s:String) => Array(s.trim.replaceAll(" +", " ")))
//error: object java.lang.String is not a value --> use Array

val data = List("i  like    cheese", "  the dog runs   ", "text111111   text2222222")
val df = data.toDF("val")
df.show()

val new_df = df
  .withColumn("udfResult",myUDf(col("val")))
  .withColumn("new_val", col("udfResult")(0))
  .drop("udfResult")
new_df.show