When you assign raw values to enum, you have to define the type in your enum syntax and give value for each case:

enum IntEnum: Int{ 
   case case1 = 50 
   case case2 = 60 
   case case3 = 100 
} 

Swift gives you flexibility while dealing with raw values. You don't have to explicitly assign a raw value for each case in enums if the type of enum is Int or String. For Int type enums, the default value of enum is equal to the value of previous one + 1. In case of the first case, by default it's equal to 0. Let's take a look at this example:

enum Gender: Int{ 
   case Male 
   case Female 
   case Other 
} 
var maleValue = Gender.Male.rawValue  // 0 
var femaleValue = Gender.Female.rawValue // 1 

We didn't set any raw value for any case, so the compiler automatically will set the first one to 0, as it's a no set. For any following case, it's value will be equal to previous case value + 1. Another note is that .rawValue returns the explicit value of the enum case. Let's take a look at another complex example that will make it crystal clear:

enum HTTPCode: Int{ 
   case OK = 200 
   case Created  // 201 
   case Accepted // 202 
   case BadRequest = 400 
   case UnAuthorized 
   case PaymentRequired 
   case Forbidden 
    
} 
 
let pageNotFound = HTTPCode.NotFound 
let errorCode = pageNotFound.rawValue  // 404 

We have explicitly set the value of first case to 200; so, the following two cases will be set to 201 and 202, as we didn't set raw values for them. The same will happen for BadRequest case and the following cases. For example, the NotFound case is equal to 404 after incrementing cases.

Now, we see how Swift compiler deals with Int type when you don't give explicit raw values for some cases. In case of String, it's pretty easier. The default value of String enum cases will be the case name itself. Let's take a look at an example:

enum Season: String{ 
   case Winter 
   case Spring 
   case Summer 
   case Autumn 
} 
 
let winter = Season.Winter 
 
let statement = "My preferred season is " + winter.rawValue // "My preferred season is Winter" 

You can see that we could use the string value of rawValue of seasons to append it to another string.

We saw how easy it is to create enums with raw values. Now, let's take a look at how to get the raw value of enums or create enums back using raw values.

We already saw how to get the raw value from enum by just calling .rawValue to return the raw value of the enum case.

To initialize an enum with a raw value, the enum should be declared with a type; so in that case, the enum will have a default initializer to initialize it with a raw value. An example of an initializer will be like this:

let httpCode = HTTPCode(rawValue: 404)  // NotFound 
let httpCode2 = HTTPCode(rawValue: 1000) // nil 

The rawValue initializer always returns an optional value because there will not be any matching enum for all possible values given in rawValue. For example, in case of 404, we already have an enum whose value is 404. However, for 1000, there is no enum with such value, and the initializer will return nil in that case. So, before using any enum initialized by the rawValue initializer, you have to check first whether the value is not equal to nil; the best way to check for enums after initialization is by this method:

if let httpCode = HTTPCode(rawValue: 404){ 
   print(httpCode) 
} 
if let httpCode2 = HTTPCode(rawValue: 1000){ 
   print(httpCode2) 
} 

The condition will be true only if the initializer succeeds to find an enum with the given rawValue.