How do I make a structure conform to protocol "Equatable"?
I'm using Xcode 7.3.1
struct MyStruct {
var id: Int
var value: String
init(id: Int, value: String) {
self.id = id
self.value = value
}
var description: String {
return "blablabla"
}
}
When I use "MyStruct", Xcode shows the error:
MyStruct does not conform to protocol "Equatable"
Do you have an idea to make MyStruct conform to protocol?
Starting from Swift 4.1, all you have to is to conform to the Equatable
protocol without the need of implementing the ==
method. See: SE-0185 - Synthesizing Equatable and Hashable conformance.
Example:
struct MyStruct: Equatable {
var id: Int
var value: String
}
let obj1 = MyStruct(id: 101, value: "object")
let obj2 = MyStruct(id: 101, value: "object")
obj1 == obj2 // true
Keep in mind that the default behavior for the ==
is to compare all the type properties (based on the example: lhs.id == rhs.id && lhs.value == rhs.value
). If you are aiming to achieve a custom behavior (comparing only one property for instance), you have to do it by yourself:
struct MyStruct: Equatable {
var id: Int
var value: String
}
extension MyStruct {
static func ==(lhs: MyStruct, rhs: MyStruct) -> Bool {
return lhs.id == rhs.id
}
}
let obj1 = MyStruct(id: 101, value: "obj1")
let obj2 = MyStruct(id: 101, value: "obj2")
obj1 == obj2 // true
At this point, the equality would be based on the id
value, regardless of what's the value of value
.