How to find the last occurrence of an element in a Scala List?

Question

I have a List of Students from which I want to find the last matching student whose age is 23.

I know that find() method gives us the first matching occurrence as shown below:

case class Student(id: Int, age: Int)

val students = List(Student(1, 23), Student(2, 24), Student(3, 23))

val firstStudentWithAge23 = students.find(student => student.age == 23)
// Some(Student(1, 23))

This code gives me the first matching student. But I need the last matching student.

For now, I am using reverse method followed by find:

val lastStudentWithAge23 = students.reverse.find(student => student.age == 23)
// Some(Student(3,23))

This gives me the last matching student.

But this doesn't not seem to be a good approach since the whole list has to be reversed first. How can I achieve this in a better yet functional way ?

Answer 1

As of Scala 2.13, you can use findLast to find the last element of a Seq satisfying a predicate, if one exists:

val students = List(Student(1, 23), Student(2, 24), Student(3, 23))
students.findLast(_.age == 23) // Option[Student] = Some(Student(3, 23))