entityMap|blocks|key|c1520|text|检查此代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|281a3|func+demo(){

++++var+str+=+[String:+String]()

++++str["status"]+=+"blue"
++++str["asd"]+=+nil

++++guard+let+var2+=+str["asd"],+let+var1+=+str["status"]
++++else
++++{
++++++++print("asdsfddffgdfgdfga")
++++++++return
++++}
++++print("asdasdasd")
}|code-block|syntax|javascript|1tjr0|守卫将逐一检查情况。如果第一个为真，那么它将检查下一个。否则，它将执行|7f9n9|否则|16a6i|部分。^0|0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|N|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|O|9|@]|A|@]|B|$F|G]]|$2|H|4|I|6|7|8|P|9|@]|A|@]|B|$]]|$2|J|4|K|6|7|8|Q|9|@]|A|@]|B|$]]|$2|L|4|M|6|7|8|R|9|@]|A|@]|B|$]]]]

Check this code
<pre><code>func demo(){

 var str = [String: String]()

 str[&quot;status&quot;] = &quot;blue&quot;
 str[&quot;asd&quot;] = nil

 guard let var2 = str[&quot;asd&quot;], let var1 = str[&quot;status&quot;]
 else
 {
 print(&quot;asdsfddffgdfgdfga&quot;)
 return
 }
 print(&quot;asdasdasd&quot;)
}
</code></pre>
Guard will check one by one condition. If the first is true then it will check the next. Otherwise, it will execute the else part.

entityMap|blocks|key|cqoo8|text|为了回答Prabhav的问题，是的，你是正确的，在一个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70rqq|守卫|ejkun|语句必须为true才能继续(即，不进入else块)。从这个意义上说，它确实像是用AND逻辑分隔条件。|67l6a|你|6a1dm|可以|engqq|实现OR逻辑，不是使用逗号，而是使用布尔条件：|5b21m|guard
++++true+%7C%7C+false++++//+this+guard+statement+evaluates+to+true
else
++++{
++++print("no,+not+all+values+in+the+guard+were+true")
++++return
++++}

print("yes,+all+of+the+values+in+the+guard+were+true")++//+this+is+printed|code-block|syntax|javascript|99fkg|或or与and逻辑的组合，通过使用布尔条件和可选绑定的组合：|7cbh5|let+testString:+String?+=+nil

guard
++++true+%7C%7C+false,
++++let+x+=+testString,++++//+this+guard+statement+evaluates+to+false
++++true
else
++++{
++++print("no,+not+all+values+in+the+guard+were+true")++//+this+is+printed
++++return
++++}

print("yes,+all+of+the+values+in+the+guard+were+true")|bcorc|这篇来自Apple的摘要，是关于可选绑定的|6l05|如果|7kv7p|语句同样适用于|64cmh|cd5h2|声明：|5haai|您可以根据需要在单个if语句中包含任意多个可选绑定和布尔条件，用逗号分隔。如果可选绑定中的任意值为nil或任何布尔条件的计算结果为false，则整个If语句的条件都被视为false。以下if语句是等效的：|ag5ns|if+let+firstNumber+=+Int("4"),+let+secondNumber+=+Int("42"),
++++firstNumber+<+secondNumber+&&+secondNumber+<+100
++++{
++++print("\(firstNumber)+<+\(secondNumber)+<+100")
++++}+//+Prints+"4+<+42+<+100"

if+let+firstNumber+=+Int("4")
++++{
++++if+let+secondNumber+=+Int("42")
++++++++{
++++++++if+firstNumber+<+secondNumber+&&+secondNumber+<+100
++++++++++++{
++++++++++++print("\(firstNumber)+<+\(secondNumber)+<+100")
++++++++++++}
++++++++}
++++}+//+Prints+"4+<+42+<+100"^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|18|9|@]|A|@]|B|$]]|$2|C|4|D|6|7|8|19|9|@]|A|@]|B|$]]|$2|E|4|F|6|7|8|1A|9|@]|A|@]|B|$]]|$2|G|4|H|6|7|8|1B|9|@]|A|@]|B|$]]|$2|I|4|J|6|7|8|1C|9|@]|A|@]|B|$]]|$2|K|4|L|6|7|8|1D|9|@]|A|@]|B|$]]|$2|M|4|N|6|O|8|1E|9|@]|A|@]|B|$P|Q]]|$2|R|4|S|6|7|8|1F|9|@]|A|@]|B|$]]|$2|T|4|U|6|O|8|1G|9|@]|A|@]|B|$P|Q]]|$2|V|4|W|6|7|8|1H|9|@]|A|@]|B|$]]|$2|X|4|Y|6|7|8|1I|9|@]|A|@]|B|$]]|$2|Z|4|10|6|7|8|1J|9|@]|A|@]|B|$]]|$2|11|4|D|6|7|8|1K|9|@]|A|@]|B|$]]|$2|12|4|13|6|7|8|1L|9|@]|A|@]|B|$]]|$2|14|4|15|6|7|8|1M|9|@]|A|@]|B|$]]|$2|16|4|17|6|O|8|1N|9|@]|A|@]|B|$P|Q]]]]

To answer Prabhav's question, yes, you are correct, each condition in a guard statement must be true in order to proceed (i.e., not go into the else block). In this sense, it is indeed like separating conditions with AND logic.

You can implement OR logic, not by using commas, but by using a Boolean condition:

<pre><code>guard
 true || false // this guard statement evaluates to true
else
 {
 print("no, not all values in the guard were true")
 return
 }

print("yes, all of the values in the guard were true") // this is printed
</code></pre>

or a combination of OR and AND logic, by using a combination of Boolean conditions and optional bindings:

<pre><code>let testString: String? = nil

guard
 true || false,
 let x = testString, // this guard statement evaluates to false
 true
else
 {
 print("no, not all values in the guard were true") // this is printed
 return
 }

print("yes, all of the values in the guard were true")
</code></pre>

This summary from Apple, written about optional bindings in if statements is equally applicable to guard statements:

<blockquote>
 You can include as many optional bindings and Boolean conditions in a
 single if statement as you need to, separated by commas. If any of the
 values in the optional bindings are nil or any Boolean condition
 evaluates to false, the whole if statement’s condition is considered
 to be false. The following if statements are equivalent:
</blockquote>

<pre><code>if let firstNumber = Int("4"), let secondNumber = Int("42"),
 firstNumber &lt; secondNumber &amp;&amp; secondNumber &lt; 100
 {
 print("\(firstNumber) &lt; \(secondNumber) &lt; 100")
 } // Prints "4 &lt; 42 &lt; 100"

if let firstNumber = Int("4")
 {
 if let secondNumber = Int("42")
 {
 if firstNumber &lt; secondNumber &amp;&amp; secondNumber &lt; 100
 {
 print("\(firstNumber) &lt; \(secondNumber) &lt; 100")
 }
 }
 } // Prints "4 &lt; 42 &lt; 100"
</code></pre>

Is there a way to include multiple conditions in a guard statement of Swift?
For example, if I want to check two optional values are nil using a guard, how should I do it using single guard statement?

Multiple conditions in guard statement in Swift

Swift

 有没有办法在Swift的guard语句中包含多个条件？ 例如，如果我想使用guard检查两个可选值为零，我应该如何使用单个guard语句来实现？

问Swift中guard语句中的多个条件
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