Find prime numbers using Scala. Help me to improve

Question

I wrote this code to find the prime numbers less than the given number i in scala.

def findPrime(i : Int) : List[Int] = i match {
    case 2 => List(2)
           


        

Answer 1

A scalar fp approach

// returns the list of primes below `number`
def primes(number: Int): List[Int] = {
    number match {
        case a
        if (a <= 3) => (1 to a).toList
        case x => (1 to x - 1).filter(b => isPrime(b)).toList
    }
}

// checks if a number is prime
def isPrime(number: Int): Boolean = {
    number match {
        case 1 => true
        case x => Nil == {
            2 to math.sqrt(number).toInt filter(y => x % y == 0)
        }
    }
}