Swift之For-In-Where

GitHub Demo: https://github.com/BaHui/BHSwifter

简介

For-In-Where 和 For-In 的用法相同, 都是用来遍历, 只不过是前者将限制条件外置, 跟随在Where之后;

使用示例

import UIKit

// 定义ClassA
class ClassA: NSObject {}

// 定义ClassB
class ClassB: NSObject {}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let objectA = ClassA()
        let objectB = ClassB()
        let objectArray = [objectB, objectA, objectB]

        for object in objectArray where (object is ClassB) {
            print("`ClassB`实例对象, 位于的Index: \(objectArray.firstIndex(of: object)!)")
            break
        }
        // `ClassB`实例对象, 位于的Index: 0 (用了break关键字)
    }

}

交流与建议

• GitHub：https://github.com/BaHui
• 邮    箱：qiaobahuiyouxiang@163.com