Validate that sequence of numbers are within allowed range - scala

Question

How can I validate that a sequence of numbers falls into an allowed range of numbers in a more scala/functional (not java like) way?
val valuesRight = Seq(1, 2, 3, 4, 5, 6, 7)
val valuesWrong = Seq(1, 2, 5, 6, 7, 8, 9)
val allowedValues = Range(1, 8)
def containsNotAllowedValues(allowed: Range, input: Seq[Int]): Boolean = {
var containsNotAllowedValue = false
// pseudo code of how to do it in java, But how in scala / functional way?
while next element is available
validate if it is contained in allowed
if not allowed set containsNotAllowedValue to true and break the loop early
}
containsNotAllowedValue
}
containsNotAllowedValues(allowedValues, valuesRight) // expected false as no wrong element contained
containsNotAllowedValues(allowedValues, valuesWrong) // expected true as at least single wrong element is contained

Answer 1

You can use the forall function on Seq. It checks whether the given predicate is true for all elements in the Seq. If that function returns false with the predicate allowed contains _, then your Seq contains an illegal value.
def containsNotAllowedValues(allowed: Range, input: Seq[Int]): Boolean =
!input.forall { allowed contains _ }

Answer 2

You could do something as simple as this:
def containsNotAllowedValues(allowed: Range, input: Seq[Int]): Boolean = {
!(allowed.head <= input.min && allowed.last >= input.max)
}
val valuesRight = Seq(1, 2, 3, 4, 5, 6, 7)
val valuesWrong = Seq(1, 2, 5, 6, 7, 8, 9)
val allowedValues = Range(1, 8)
containsNotAllowedValues(allowedValues,valuesRight) //false
containsNotAllowedValues(allowedValues,valuesWrong) //true
This will fail if the Range has only 1 value like Range(1,1)
If you want you can add
allowed.size>1
to catch those cases