Using pattern matching to filter array - swift

Question

this is my code:
enum SymptomPeriod {
case Day
case Night
}
enum SymptomType {
case Breathing(SymptomPeriod)
case Breathlessness(SymptomPeriod)
case Opression(SymptomPeriod)
case Cough(SymptomPeriod)
case ActivityLimited()
case SecureTreatment()
}
struct Symptom {
let type: SymptomType
let date: NSDate
}
And i have an array of symptoms.
let symptomList: [Symptom] = ...
My need is to filter the list of symptoms with the SymptomPerion criteria, i trying to do like this:
let daySymtoms = symptomList.filter { (symptom) -> Bool in
return symptom.type = ???
}
My problem is in the filter function.
(My goal is to use a filter function and not a loop)

Answer 1

A few suggestions
Use your struct as namespace
Instead of repeating the word Symptom (e.g. SymptomPeriod, SymptomType) you should put your enums into you Symptom struct
Rename SymptomType as Kind
Once you moved SymptomType into Symptom you can drop the Symptom part of the name. However using Type as name will create a conflict so you should rename it Kind.
Add the period computed property to Kind
This will make the filtering much easier
Here's the code
struct Symptom {
enum Period {
case Day
case Night
}
enum Kind {
case Breathing(Period)
case Breathlessness(Period)
case Opression(Period)
case Cough(Period)
case ActivityLimited()
case SecureTreatment()
var period: Period? {
switch self {
case Breathing(let period): return period
case Breathlessness(let period): return period
case Opression(let period): return period
case Cough(let period): return period
default: return nil
}
}
}
let kind: Kind
let date: NSDate
}
The solution
Now the filtering has become very easy
let symptoms: [Symptom] = ...
let filtered = symptoms.filter { $0.kind.period == .Day }

Answer 2

This is how i am doing it:
let daySymtoms = symtoms.filter { (symptom) -> Bool in
switch symptom.type {
case .Breathing(.Day), .Breathlessness(.Day), .Opression(.Day), .Cough(.Day):
return true
default:
return false
}
}
Let me know if you have more simple way to do it.