ios - 快速将 if else 结构转换为 switch case

Question

我是编程新手，我正在尝试将此 if else 结构转换为 Swift 语言的 Switch 案例，非常感谢您的帮助，谢谢。

这是我的代码

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if (segue.identifier == "ShowDefinition") {
        if let destinationViewController = segue.destinationViewController as? EnglishViewController {
            if let definition = sender as? String {
                if definition == "Abstraction" {
                    destinationViewController.titleMsg = "Abstraction"
                    destinationViewController.definitionMsg = "definition 1"
                } else if definition == "Binary System" {
                    destinationViewController.titleMsg = "Binary System"
                    destinationViewController.definitionMsg = "definition 2"
                } else if definition == "Computer" {
                    destinationViewController.titleMsg = "Computer"
                    destinationViewController.definitionMsg = "definition 3"

                } else if definition == "Internet" {
                    destinationViewController.titleMsg = "Internet"
                    destinationViewController.definitionMsg = "definition 4"

                } else if definition == "Virtual Reality" {
                    destinationViewController.titleMsg = "Virtual Reality"
                    destinationViewController.definitionMsg = "definition 5"

                }
            }
        }
    }
}

Answer 1

像这样:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if (segue.identifier == "ShowDefinition") {
        if let destinationViewController = segue.destinationViewController as? EnglishViewController {
            if let definition = sender as? String {
                switch definition {
                case "Abstraction":
                    destinationViewController.titleMsg = "Abstraction"
                    destinationViewController.definitionMsg = "definition 1"
                case "Binary System":
                    destinationViewController.titleMsg = "Binary System"
                    destinationViewController.definitionMsg = "definition 2"
                case "Computer":
                    destinationViewController.titleMsg = "Computer"
                    destinationViewController.definitionMsg = "definition 3"
                case "Internet":
                    destinationViewController.titleMsg = "Internet"
                    destinationViewController.definitionMsg = "definition 4"
                    destinationViewController.titleMsg = "Abstraction"
                    destinationViewController.definitionMsg = "definition 1"
                case "Virtual Reality":
                    destinationViewController.titleMsg = "Virtual Reality"
                    destinationViewController.definitionMsg = "definition 5"
                default:
                    destinationViewController.titleMsg = ""
                    destinationViewController.definitionMsg = ""
                }
            }
        }
    }
}

检查你想用 default 值做什么，如果没有 case 匹配，将被命中。