blocks|key|1890211|text|您可以相应地返回所需的值：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1890212|switch+diff+{
case+0:
++++print("Bull+Eye")
case+1..<10:
++++print("Almost+Bull+Eye")
case+10..<30:
++++print("Close")
default:
++++print("Too+Far")
}|code-block|syntax|javascript|1890213|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can return the values you want accordingly:
<pre><code>switch diff {
case 0:
 print(&quot;Bull Eye&quot;)
case 1..&lt;10:
 print(&quot;Almost Bull Eye&quot;)
case 10..&lt;30:
 print(&quot;Close&quot;)
default:
 print(&quot;Too Far&quot;)
}
</code></pre>

blocks|key|1045751|text|您必须在switch语句中使用范围操作符作为大小写：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1045752|a...b+//它的范围从a到b，意味着b也包括在内
a..<b+//它的范围从a到b-1，意味着b不包括在内。|blockquote|offset|length|style|CODE|1045753|private+func+calculateUserScore()+->+Int+{
++++let+diff+=+abs(randomNumber+-+Int(bullsEyeSlider.value))
++++switch+diff+{
++++case+0:+return+PointsAward.bullseye.rawValue
++++case+1..<10:+return+PointsAward.almostBullseye.rawValue
++++case+10..<30:+return+PointsAward.close.rawValue
++++default:+return+0
++++}
}|code-block|syntax|javascript|1045754|entityMap^0|0|0|5|R|5|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Q|8|@$E|R|F|S|G|H]|$E|T|F|U|G|H]]|9|@]|A|$]]|$1|I|3|J|5|K|7|V|8|@]|9|@]|A|$L|M]]|$1|N|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|O|$]]

You have to use range-operators as case in switch-statement:
<blockquote>
<code>a...b</code> // It have range from a to b, means b is included as well
<code>a..&lt;b</code> // It have range from a to b-1, means b is not included
</blockquote>
<pre><code>private func calculateUserScore() -&gt; Int {
 let diff = abs(randomNumber - Int(bullsEyeSlider.value))
 switch diff {
 case 0: return PointsAward.bullseye.rawValue
 case 1..&lt;10: return PointsAward.almostBullseye.rawValue
 case 10..&lt;30: return PointsAward.close.rawValue
 default: return 0
 }
}
</code></pre>

blocks|key|1045797|text|只为你：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1045798|enum+PointsAward:+Int+{
++++case+close
++++case+almostBullseye
++++case+bullseye
}

private+func+calculateUserStory()+->+Int+{
++++let+bullsEyeSliderValue+=+9
++++let+randomNumber+=+100
++++let+diff+=+abs(randomNumber+-+Int(bullsEyeSliderValue))
++++switch+diff+{
++++case+0:
++++++++return+PointsAward.bullseye.rawValue
++++case+0..<10:
++++++++return+PointsAward.almostBullseye.rawValue
++++case+0..<30:
++++++++return+PointsAward.close.rawValue
++++default:+return+0
++++}
}|code-block|syntax|javascript|1045799|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Only for you:

<pre><code>enum PointsAward: Int {
 case close
 case almostBullseye
 case bullseye
}

private func calculateUserStory() -&gt; Int {
 let bullsEyeSliderValue = 9
 let randomNumber = 100
 let diff = abs(randomNumber - Int(bullsEyeSliderValue))
 switch diff {
 case 0:
 return PointsAward.bullseye.rawValue
 case 0..&lt;10:
 return PointsAward.almostBullseye.rawValue
 case 0..&lt;30:
 return PointsAward.close.rawValue
 default: return 0
 }
}
</code></pre>

blocks|key|1045823|text|这应该能行。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1045824|private+func+calculateUserScore()+->+Int+{
++++let+diff+=+abs(randomNumber+-+Int(bullsEyeSlider.value))
++++switch+diff+{
++++case+0:
++++++++return+PointsAward.bullseye.rawValue
++++case+1..<10:
++++++++return+PointsAward.almostBullseye.rawValue
++++case+10..<30:
++++++++return+PointsAward.close.rawValue
++++default:
++++++++return+0
++++}
}|code-block|syntax|javascript|1045825|它在控制下的Swift编程语言书中，->区间匹配。|offset|length|1045826|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.swift.org/swift-book/LanguageGuide/ControlFlow.html^0|0|0|6|9|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

This should work.

<pre><code>private func calculateUserScore() -&gt; Int {
 let diff = abs(randomNumber - Int(bullsEyeSlider.value))
 switch diff {
 case 0:
 return PointsAward.bullseye.rawValue
 case 1..&lt;10:
 return PointsAward.almostBullseye.rawValue
 case 10..&lt;30:
 return PointsAward.close.rawValue
 default:
 return 0
 }
}
</code></pre>

It's there in the <a href="https://docs.swift.org/swift-book/LanguageGuide/ControlFlow.html" rel="noreferrer">The Swift Programming Language</a> book under Control Flow -> Interval Matching.

blocks|key|1045835|text|在我的例子中，编译器将CGFloat作为一个封闭的double范围，所以我必须显式地告诉编译器我正在检查CGFloat范围。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1045836|+++var+progress:+CGFloat!
+++switch+CGFloat(progress)+{
++++case+0+...+0.25:
++++++++barColor+=+.red
++++case+0.25+...+0.5:
++++++++barColor+=+.yellow
++++default:
++++++++break
++++}|code-block|syntax|javascript|1045837|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In my case the compiler took CGFloat as a closed range of double, so I had to explicitly tell compiler that I am checking CGFloat range. 

<pre><code> var progress: CGFloat!
 switch CGFloat(progress) {
 case 0 ... 0.25:
 barColor = .red
 case 0.25 ... 0.5:
 barColor = .yellow
 default:
 break
 }
</code></pre>

blocks|key|335973|text|如果您需要检查一个值是否大于任何数字，或者在两个值之间使用，则可以使用where而不是if，这样会更干净一些。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|335974|func+isOutdated(days:+Int)+->+Outdated+{

++++var+outdatedStatus+=+Outdated.none

++++switch+days+{
++++case+_+where+days+<+5:
++++++++outdatedStatus+=+.tooLow
++++case+5...10:
++++++++outdatedStatus+=+.low
++++case+11...20:
++++++++outdatedStatus+=+.high
++++case+_+where+days+>+20:
++++++++outdatedStatus+=+.expired
++++default:
++++++++outdatedStatus+=+.none
++++}
++++return+outdatedStatus
}|code-block|syntax|javascript|335975|entityMap^0|Z|5|17|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

In case that you need to check if a value is bigger than any number or between 2 values use it is possible to use <code>where</code> instead of <code>if</code> looks a bit cleaner this will work
<pre><code>func isOutdated(days: Int) -&gt; Outdated {

 var outdatedStatus = Outdated.none

 switch days {
 case _ where days &lt; 5:
 outdatedStatus = .tooLow
 case 5...10:
 outdatedStatus = .low
 case 11...20:
 outdatedStatus = .high
 case _ where days &gt; 20:
 outdatedStatus = .expired
 default:
 outdatedStatus = .none
 }
 return outdatedStatus
}
</code></pre>

I'm learning Swift and tried to program the game "Bullseye" from Ryan Wenderlich by my own before watching the videos.

I needed to give the user points depending on how close to the target number he was. I tried to calculate the difference and than check the range and give the user the points, This is what I did with If-else (Couldn't do it with switch case):

<pre><code>private func calculateUserScore() -&gt; Int {
 let diff = abs(randomNumber - Int(bullsEyeSlider.value))
 if diff == 0 {
 return PointsAward.bullseye.rawValue
 } else if diff &lt; 10 {
 return PointsAward.almostBullseye.rawValue
 } else if diff &lt; 30 {
 return PointsAward.close.rawValue
 }
 return 0 // User is not getting points. 
}
</code></pre>

Is there a way to do it more elegantly or with Switch-Case?
I couldn't just do <code>diff == 0</code> for example in the case in switch case as xCode give me an error message.

Switch case with range

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在学习斯威夫特，在看视频之前，我试着用我自己的瑞恩·温德利希()来编写游戏“牛眼”(Bullseye)。我需要给用户点，这取决于他离目标号码有多近。我试图计算差异，而不是检查范围和给用户点，这是我做的If-否则(不能用开关的情况)：private func calculateUserScore() -> Int {...

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