从 Swift 元组数组中投影一列

Question

我有一个 Swift 元组数组，Persons = [(name:String, age:Int)]。 现在我想从Persons 数组中提取字符串数组name:[String] 中的所有不同名称。我怎样才能得到它。

Answer 1

let distinctNames = Set(Persons.map { $0.name })

Answer 2

小代码示例教你如何使用map函数：

struct Person {
        let name: String
        let age: Int
}

let people = [
    Person(name: "Oleg",  age: 24),
    Person(name: "Igor",    age: 26),
]

let names: [String] = people.map { return $0.name }