Scala: not save modify sequence when exit to foreach

Question

I´m trying to create a Dataframe with any sequences and for obtain this sequences, I have the folow implementation.

I have a initial Dataframe and I iterate on it with a foreach. In condition of the values of the diferents columns of this Dataframe, i modify a empty Seq with the values i have. This Sequence is initialize empty below of the loop.

At end of the loop, the sequence is empty again.why?

var seq1 =  Seq.empty[Long]  

df1.foreach(r=>{
      if ( r(2) < CountAw1p) {
        if (r(1) == "T-F") {
          countTF = countTF + r(2)
        } else if (r(1) == "T-D") {
          countTD = countTD + r(2)
        }
      } else {
        var rest = CountAw1p - (countTF + countTD)
        rest = r(2) - rest
        if (r(1) == "T-F") {
          countTF = countTF + rest
          seq1 = seq1 ++ Seq(countTF, countTD) //seq is full
        } else if (r(1) == "T-D") {
          countTD = countTD + rest
          seq1 = seq1 ++ Seq(countTF, countTD)//seq is full
        }
      }
    })

    val completInfo = Seq(seq1).toDF() //seq is empty
    return completInfo