spark override the dataframe variable without using var










0















I have one API which perform delete operation on dataframe like below



def deleteColmns(df:DataFrame,clmList :List[org.apache.spark.sql.Column]):DataFrame
var ddf:DataFrame = null
for(clm<-clmList)
ddf.drop(clm)

return ddf



Since it is not good practice to use the var in functional programming , how to avoid this situation










share|improve this question


























    0















    I have one API which perform delete operation on dataframe like below



    def deleteColmns(df:DataFrame,clmList :List[org.apache.spark.sql.Column]):DataFrame
    var ddf:DataFrame = null
    for(clm<-clmList)
    ddf.drop(clm)

    return ddf



    Since it is not good practice to use the var in functional programming , how to avoid this situation










    share|improve this question
























      0












      0








      0








      I have one API which perform delete operation on dataframe like below



      def deleteColmns(df:DataFrame,clmList :List[org.apache.spark.sql.Column]):DataFrame
      var ddf:DataFrame = null
      for(clm<-clmList)
      ddf.drop(clm)

      return ddf



      Since it is not good practice to use the var in functional programming , how to avoid this situation










      share|improve this question














      I have one API which perform delete operation on dataframe like below



      def deleteColmns(df:DataFrame,clmList :List[org.apache.spark.sql.Column]):DataFrame
      var ddf:DataFrame = null
      for(clm<-clmList)
      ddf.drop(clm)

      return ddf



      Since it is not good practice to use the var in functional programming , how to avoid this situation







      apache-spark apache-spark-sql






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 15 '18 at 13:25









      user3607698user3607698

      378117




      378117






















          1 Answer
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          active

          oldest

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          3














          With Spark >2.0, you can drop multiple columns using a sequence of column name :



          val clmList: Seq[Column] = _
          val strList: Seq[String] = clmList.map(c => s"$c")
          df.drop(strList: _*)


          Otherwise, you can always use foldLeft to fold left on the DataFrame and drop your columns :



          clmList.foldLeft(df)((acc, c) => acc.drop(c))


          I hope this helps.






          share|improve this answer
























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            1 Answer
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            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3














            With Spark >2.0, you can drop multiple columns using a sequence of column name :



            val clmList: Seq[Column] = _
            val strList: Seq[String] = clmList.map(c => s"$c")
            df.drop(strList: _*)


            Otherwise, you can always use foldLeft to fold left on the DataFrame and drop your columns :



            clmList.foldLeft(df)((acc, c) => acc.drop(c))


            I hope this helps.






            share|improve this answer





























              3














              With Spark >2.0, you can drop multiple columns using a sequence of column name :



              val clmList: Seq[Column] = _
              val strList: Seq[String] = clmList.map(c => s"$c")
              df.drop(strList: _*)


              Otherwise, you can always use foldLeft to fold left on the DataFrame and drop your columns :



              clmList.foldLeft(df)((acc, c) => acc.drop(c))


              I hope this helps.






              share|improve this answer



























                3












                3








                3







                With Spark >2.0, you can drop multiple columns using a sequence of column name :



                val clmList: Seq[Column] = _
                val strList: Seq[String] = clmList.map(c => s"$c")
                df.drop(strList: _*)


                Otherwise, you can always use foldLeft to fold left on the DataFrame and drop your columns :



                clmList.foldLeft(df)((acc, c) => acc.drop(c))


                I hope this helps.






                share|improve this answer















                With Spark >2.0, you can drop multiple columns using a sequence of column name :



                val clmList: Seq[Column] = _
                val strList: Seq[String] = clmList.map(c => s"$c")
                df.drop(strList: _*)


                Otherwise, you can always use foldLeft to fold left on the DataFrame and drop your columns :



                clmList.foldLeft(df)((acc, c) => acc.drop(c))


                I hope this helps.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited Nov 15 '18 at 21:46

























                answered Nov 15 '18 at 14:03









                eliasaheliasah

                27.5k774117




                27.5k774117





























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