Array as a dictionary

arrAsDict.swift

struct Model {
    var id: String
    var value: Int
}

var arrAsDict = [
    Model(id: "foo", value: 2),
    Model(id: "bar", value: 5)
]

extension Array where Element == Model {
    subscript(_ id: String) -> Model? {
        filter { $0.id == id }.first
    }
    subscript(_ model: Model) -> String? {
        filter { $0.id == model.id }.first?.id
    }
}

print(arrAsDict["foo"]?.value)
print(arrAsDict["bar"]?.value)