9

I want a enumeration of countries, like:

enum Country: Int {
    case Afghanistan
    case Albania
    case Algeria
    case Andorra
    //...
}

There are two main reasons why I choose Int as its rawValue type:

  1. I want to determine the total count of this enumeration, using Int as rawValue type simplifies this:

    enum Country: Int {
    case Afghanistan
    // other cases
    static let count: Int = {
        var max: Int = 0
        while let _ = Country(rawValue: max) { max = max + 1 }
        return max
    }()
}

  2. I also need a complicated data structure that represents a country, and there is an array of that data structure. I can easily subscript-access certain country from this array using Int-valued enumeration.

    struct CountryData {
     var population: Int
     var GDP: Float
}

var countries: [CountryData]

print(countries[Country.Afghanistan.rawValue].population)

Now, I somehow need to convert a certain Country case to String(aka. something like 

let a = Country.Afghanistan.description // is "Afghanistan"

Since there are lots of cases, manually writing a conversion-table-like function seems unacceptable.

So, how can I get these features at once ?:

  1. Use enumeration so potential typo-caused bugs can be found during compile time. (Country.Afganistan won't compile, there should be an 'h' after 'g', but some approach like countries["Afganistan"] will compile and may cause runtime errors)
  2. Be able to determine the total country count programmatically (likely to be able to determine at the compile time, but I don't want to use a literal value and keep in mind to change it properly every time I add or remove a country)
  3. Be able to easily subscript-like access a metadata array.
  4. Be able to get a string of a case.

Using enum Country: Int satisfies 1, 2, 3 but not 4

Using enum Country: String satisfies 1, 3, 4 but not 2 (use Dictionary instead of Array)

Nandin Borjigin
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  • what's the mean of 'h' after 'g'? – Archerlly Mar 21 '17 at 10:30
  • This question is not a duplicate, the "rawType is Int" in this question is unique and essential the question. Answers there say to re-declare the enum as a String type. – pkamb Jul 25 '19 at 01:24

1 Answers1

9

To print an enum's case as String, use:

String(describing: Country.Afghanistan)

You can create you data structure something like:

enum Country
{
    case Afghanistan
    case Albania
    case Algeria
    case Andorra
}

struct CountryData
{
    var name : Country
    var population: Int
    var GDP: Float
}

var countries = [CountryData]()
countries.append(CountryData(name: .Afghanistan, population: 2000, GDP: 23.1))
print(countries[0].name)
PGDev
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