arrays - Swift 3 - 使类可迭代

Question

考虑我的两个类:

// Person.swift
class Person {
    var parents: Parents?
    // ...
}

// Parents.swift. Only a collection of parents with some helper methods.
class Parents {
    var parents = [Person]()
    // ...
}

如何使用 parents 的迭代器让 Parents 在 for 循环中进行迭代。这不是真实世界的应用程序。我只是好奇。只是想使用 for parent in myParents 而不是 for parent in myParents.parents。

Answer 1

做到这一点的方法是让你的 Parents类符合 Sequence Protocol , 实现 makeIterator方法，然后通过调用 makeIterator 传递结果在包含 Array<Person>

  // Person.swift
  class Person {
    var parents: Parents?
    // ...
  }

  // Parents.swift. Only a collection of parents with some helper methods.
  class Parents{
    var parents = [Person]()
    // ...
  }

  // conform to Sequence Protocol
  extension Parents: Sequence {
    func makeIterator() -> Array<Person>.Iterator {
      return parents.makeIterator()
    }
  }

  let myself = Person()
  if let myParents = myself.parents {
    for person in myParents {

    }
  }