How to implement 'takeUntil' of a list?

Question

I want to find all items before and equal the first 7:

val list = List(1,4,5,2,3,5,5,7,8,9,2,7,4)

My solution is:

Answer 1

Some ways by use built-in functions:

val list = List(1, 4, 5, 2, 3, 5, 5, 7, 8, 9, 2, 7, 4)
//> list  : List[Int] = List(1, 4, 5, 2, 3, 5, 5, 7, 8, 9, 2, 7, 4)
//Using takeWhile with dropWhile
list.takeWhile(_ != 7) ++ list.dropWhile(_ != 7).take(1)
//> res0: List[Int] = List(1, 4, 5, 2, 3, 5, 5, 7)
//Using take with segmentLength
list.take(list.segmentLength(_ != 7, 0) + 1)

//> res1: List[Int] = List(1, 4, 5, 2, 3, 5, 5, 7)
//Using take with indexOf
list.take(list.indexOf(7) + 1)
//> res2: List[Int] = List(1, 4, 5, 2, 3, 5, 5, 7)