如何在Swift中压缩解包多个选项？ [英] How do I condense unwrapping multiple optionals in Swift?

问题描述

我想解开这6个可选变量，如果它们为null，我想给它们一个空白的String值。这样我就可以将这些变量打包到一个发送到API的参数数组中。

I want to unwrap these 6 optional variables, and if they are null i want to give them a blank String value. This is so I can send these variables packaged into a parameters array that's sent to an API.

我仍然是Swift的初学者，这是我理解如何实现这一点的唯一最简单的方法，但我内心的编码器说这看起来多余和****一样蹩脚。

I'm still a beginner at Swift, and this is the only easiest way I have understood how to implement this, but the inner coder in me is saying this looks redundant and crappy as ****.

有人可以帮我缩小或简化吗？

Can someone help me condense this or make it simpler?

    if let fbEmail = self.fbEmail {

    }else{
        self.fbEmail = ""
    }

    if let fbDob = self.fbDob {

    }else{
        self.fbDob = ""
    }

    if let fbGender = self.fbGender {

    }else{
        self.fbGender = ""
    }
    if let fbUserIp = self.fbUserIp {

    }else{
        self.fbUserIp = ""
    }
    if let fbFacebookId = self.fbFacebookId {

    }else{
        self.fbFacebookId = ""
    }
    if let fbFacebookAccessToken = self.fbFacebookAccessToken {

    }else{
        self.fbFacebookAccessToken = ""
    }

推荐答案

你可以用6行代码完成：

You can do that in exactly 6 lines of code:

self.fbEmail  = self.fbEmail  ?? ""
self.fbDob    = self.fbDob    ?? ""
self.fbGender = self.fbGender ?? ""
self.fbUserIp = self.fbUserIp ?? ""
self.fbFacebookId = self.fbFacebookId ?? ""
self.fbFacebookAccessToken = self.fbFacebookAccessToken ?? ""

修改 的内容?? 语法：这是一个快捷方式如果nil指定另一个值：

what's up with the ?? syntax: It's a shortcut "if nil assign another value":

let c = a ?? b

将分配 c = a 如果 a！= nil ，否则 c = b 。

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