blocks|key|3452275|text|这是一个if语句。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3452276|左边是什么？是条件，什么是中间的？and+:是条件为真时的结果，而:右边的是条件为假时的结果。|3452277|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

That's an if statement.

What's to the left of ? is the condition, what's between the ? and : is the result if the condition is true, and what's to the right of : is the result if the condition is false.

blocks|key|3239304|text|这是ternary+operator+(http://en.wikipedia.org/wiki/?:)。当您需要一个小的if表达式时，它可以在任何地方使用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3239305|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/?%253a|1|http://en.wikipedia.org/wiki/?^0|1P|2|2|G|0|K|U|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]|$9|V|A|W|1|X]]|E|$]]|$1|F|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

This is <a href="http://en.wikipedia.org/wiki/?%3a" rel="nofollow">ternary operator</a> (<a href="http://en.wikipedia.org/wiki/?" rel="nofollow">http://en.wikipedia.org/wiki/?</a>:). It can be used anywhere when you need a small <code>if</code> expression.

blocks|key|406295|text|它是一个三元运算符，这意味着它有三个操作数，而不是像许多其他运算符那样有两个操作数。Wikipedia+on+Ternary+Operation以及如何在Java中使用它。归结为:计算布尔运算(或者仅仅是一个变量)。如果它的计算结果为true，则运算符返回值/执行:之前的代码，否则返回它之后的代码。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|406296|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Ternary_operation|1|http://en.wikipedia.org/wiki/?%253a#Java^0|3O|1|16|U|0|25|4|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]|$9|V|A|W|1|X]]|E|$]]|$1|F|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

It's a ternary operator, meaning that instead of having two operands like many other operators, it has three. <a href="http://en.wikipedia.org/wiki/Ternary_operation" rel="nofollow">Wikipedia on Ternary Operation</a> and how it's used in <a href="http://en.wikipedia.org/wiki/?%3a#Java" rel="nofollow">Java</a>. What it boils down to: the boolean operation (or just a variable) is evaluated. If it evaluates to true, the operator returns the value / executes the code before the <code>:</code>, otherwise the one after it.

blocks|key|3239307|text|它是一个三元运算符，适用于布尔值。在某些情况下，它可以作为if-else的简写，但不应该用于太复杂的事情，因为它可能很难读懂。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3239308|例如，根据条件为变量赋值：|3239309|String+message+=+doOperation()+?+"Success"+:+"Error+occurred";
System.out.println(message);|code-block|syntax|javascript|3239310|在这种情况下，如果doOperation返回一个布尔值，告诉它是否成功，那么可以在一行中分配要显示的消息。|3239311|请注意，此示例并不代表良好的编程实践。|3239312|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

It's the ternary operator and it works with booleans. It can be used as a shorthand for if-else in some cases, but shouldn't be used for too complicated things as it can be difficult to read.

An example would be assigning value to a variable depending on a condition:

<pre><code>String message = doOperation() ? "Success" : "Error occurred";
System.out.println(message);
</code></pre>

In this case, if doOperation returns a boolean telling whether it succeeded or not, the message to be shown can be assigned on a single line.

Please note that this example does not represent good programming practices.

blocks|key|406006|text|问号后面跟着一个冒号(两个点)是一个三元运算符，通常称为inline+if。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|406007|在本例中，它根据boolean_variable的值返回一个字符串。|406008|http://en.wikipedia.org/wiki/%253F|offset|length|406009|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/%253F^0|0|0|0|W|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

The question mark followed by a colon (two dots) is a ternary operator usually called inline if.

In this case it returns a string depending on the value of boolean_variable.

<a href="http://en.wikipedia.org/wiki/%3F" rel="nofollow">http://en.wikipedia.org/wiki/%3F</a>:

blocks|key|406298|text|?+:是conditional+operator。(不仅仅是:部分-在示例中，整个方法参数都是条件运算符的一种用法。)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|406299|它通常被称为三元运算符，但这只是它本质的一个方面-有三个操作数-而不是它的名称。如果Java中引入了另一个三元运算符，则该术语将变得不明确。它被称为条件运算符，因为它有一个条件(第一个操作数)，然后确定计算其他两个操作数中的哪一个。|406300|评估第一个操作数，然后根据第一个操作数是真还是假来评估第二个或第三个操作数。这最终是运算符的结果。|406301|所以就像这样：|406302|int+x+=+condition()+?+result1()+:+result2();|code-block|syntax|javascript|406303|大致相当于：|406304|int+x;
if+(condition())+{
++++x+=+result1();
}+else+{
++++x+=+result2();
}++|406305|重要的是，它不会计算另一个操作数。因此，例如，这是很好的：|406306|String+text+=+getSomeStringReferenceWhichMightBeNull();
int+usefulCharacters+=+text+==+null+?+0+:+text.length();|406307|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25^0|0|3|U|1|4|K|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@$9|1B|A|1C|1|1D]]|E|$]]|$1|F|3|G|5|6|7|1E|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|1F|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|1G|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1H|8|@]|D|@]|E|$O|P]]|$1|Q|3|R|5|6|7|1I|8|@]|D|@]|E|$]]|$1|S|3|T|5|N|7|1J|8|@]|D|@]|E|$O|P]]|$1|U|3|V|5|6|7|1K|8|@]|D|@]|E|$]]|$1|W|3|X|5|N|7|1L|8|@]|D|@]|E|$O|P]]|$1|Y|3|-4|5|6|7|1M|8|@]|D|@]|E|$]]]|Z|$10|$5|11|12|13|E|$14|15]]]]

<code>? :</code> is the <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25">conditional operator</a>. (It's not just the <code>:</code> part - the whole of the method argument is one usage of the conditional operator in your example.)

It's often called the ternary operator, but that's just an aspect of its nature - having three operands - rather than its name. If another ternary operator is ever introduced into Java, the term will become ambiguous. It's called the conditional operator because it has a condition (the first operand) which then determines which of the other two operands is evaluated.

The first operand is evaluated, and then either the second or the third operand is evaluated based on whether the first operand is true or false... and that ends up as the result of the operator.

So something like this:

<pre><code>int x = condition() ? result1() : result2();
</code></pre>

is roughly equivalent to:

<pre><code>int x;
if (condition()) {
 x = result1();
} else {
 x = result2();
} 
</code></pre>

It's important that it doesn't evaluate the other operand. So for example, this is fine:

<pre><code>String text = getSomeStringReferenceWhichMightBeNull();
int usefulCharacters = text == null ? 0 : text.length();
</code></pre>

blocks|key|406011|text|参见here。三元运算符类似于if表达式，但不同之处在于它是一个表达式-它有返回值，而if表达式没有返回值。有时你想用它让你的代码不那么混乱。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|406012|entityMap|0|LINK|mutability|MUTABLE|url|http://java.about.com/b/2009/06/06/java-term-of-the-week-ternary-operator.htm^0|2|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

See <a href="http://java.about.com/b/2009/06/06/java-term-of-the-week-ternary-operator.htm" rel="nofollow">here</a>. The ternary operator is similar to an if expression but differs in that it is an expression - it has a return value, while if expressions don't. Sometimes you want to use it to make your code a little less cluttered.

blocks|key|3239340|text|它是条件运算符，通常称为三元运算符，因为它有3个操作数:例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3239341|int+foo+=+10;
int+bar+=+foo+>+5+?+1+:+2;+//+will+be+1
int+baz+=+foo+>+15+?+3+:+4;+//+will+be+4|code-block|syntax|javascript|3239342|因此，如果boolean表达式的计算结果为true，它将返回第一个值(在冒号之前)，否则返回第二个值(在冒号之后)。|offset|length|style|CODE|3239343|您可以在Java+Language+Specification,+Chapter+15.25+Conditional+Operator+?中阅读详细信息|3239344|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25^0|0|0|5|7|L|4|0|1W|1|4|1T|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]|$I|11|J|12|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|13|8|@$I|14|J|15|K|L]]|9|@$I|16|J|17|1|18]]|A|$]]|$1|O|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

It's the conditional operator, often called ternary operator because it has 3 operands: An example would be:

<pre><code>int foo = 10;
int bar = foo &gt; 5 ? 1 : 2; // will be 1
int baz = foo &gt; 15 ? 3 : 4; // will be 4
</code></pre>

So, if the <code>boolean</code> expression evaluates to <code>true</code>, it will return the first value (before the colon), else the second value (after the colon).

You can read the specifics in the <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25">Java Language Specification, Chapter 15.25 Conditional Operator <code>?</code></a>

blocks|key|409001|text|对于您的问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|409002|三进制运算符(+|409003|The+?:+)称为条件运算符(或三元运算符)。|ordered-list-item|offset|length|style|CODE|409004|搜索java+ternery运算符|409005|它仅适用于boolean|409006|409007|原则上，ternery运算符是if/else的缩写。boolean将是if的条件，?和:之间的部分是if分支，后面的部分是else分支。|409008|请注意，条件运算符的返回类型由第一个分支决定。|409009|entityMap^0|0|0|4|2|0|0|0|0|F|2|I|4|Q|7|15|1|17|1|1E|2|1P|4|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|X|8|@$G|Y|H|Z|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|11|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|13|8|@$G|14|H|15|I|J]|$G|16|H|17|I|J]|$G|18|H|19|I|J]|$G|1A|H|1B|I|J]|$G|1C|H|1D|I|J]|$G|1E|H|1F|I|J]|$G|1G|H|1H|I|J]]|9|@]|A|$]]|$1|R|3|S|5|6|7|1I|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|U|$]]

For your questions:

<ol>
<li>The <code>?:</code> (both characters together) are called conditional operator (or ternary operator). Only both together will work.</li>
<li>Search for java ternery operator</li>
<li>It only works for boolean</li>
</ol>

In principle the ternery operator is a shortened <code>if</code>/<code>else</code>. The <code>boolean</code> will be the condition to the if, the part between <code>?</code> and <code>:</code> is the <code>if</code> branch and the part after this is the <code>else</code> branch.

Please note that the return type of the conditional operator is determined by the first branch.

blocks|key|406335|text|它的三元运算符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|406336|三元运算符或?是if+else语句的简写形式。它可用于计算表达式，并根据表达式的结果返回两个操作数中的一个。|406337|boolean+b+=+true;
String+s+=+(+b+==+true+?+"True"+:+"False"+);|code-block|syntax|javascript|406338|这将根据布尔值b的值设置字符串s的值。这可以使用if+else语句来编写，如下所示：|406339|boolean+b+=+true;
String+s;
if(b+==+true){
++++s+=+"True";
}else{
++++s+=+"False";
}|406340|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Its ternary operator.

The ternary operator or ?, is a shorthand if else statement. It can be used to evaluate an expression and return one of two operands depending on the result of the expression.

<pre><code>boolean b = true;
String s = ( b == true ? "True" : "False" );
</code></pre>

This will set the value of the String s according to the value of the boolean b. This could be written using an if else statement like this:

<pre><code>boolean b = true;
String s;
if(b == true){
 s = "True";
}else{
 s = "False";
}
</code></pre>

blocks|key|3239396|text|这是if-else语句的一种简短形式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3239397|它是这样工作的，|offset|length|style|BOLD|3239398|(yourCondition+?+STATEMENT1+:+STATEMENT2)|code-block|syntax|javascript|3239399|编译器将检查它返回的condition.|3239400|IF，然后将执行executed.|unordered-list-item|CODE|3239401|
|3239402|ELSE+STATEMENT1+STATEMENT2。|3239403|3239404|entityMap^0|0|0|8|0|0|0|0|2|0|0|0|4|5|A|G|A|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|10|8|@$D|11|E|12|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|13|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|P|5|Q|7|15|8|@$D|16|E|17|F|R]]|9|@]|A|$]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|Q|7|19|8|@$D|1A|E|1B|F|R]|$D|1C|E|1D|F|R]|$D|1E|E|1F|F|R]]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]|$1|X|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]]|Y|$]]

Its a short form of if-else statement.

It works in this way

<pre><code>(yourCondition ? STATEMENT1 : STATEMENT2)
</code></pre>

<ul>
<li>The compiler checks for the condition.</li>
<li><code>IF</code> it returns <code>TRUE</code> then <code>STATEMENT1</code> will be executed.</li>
<li><code>ELSE</code> <code>STATEMENT2</code> will be executed.</li>
</ul>

I came across this syntax:

<pre><code>System.out.println(boolean_variable ? "print true": "print false");
</code></pre>

<ul>
<li>What is this syntax with two dots : called? </li>
<li>Where can I find info about it?</li>
<li>Does it work just for booleans or is it implemented in other different ways?</li>
</ul>

Java: boolean in println (boolean ? "print true":"print false")

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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我遇到了这样的语法：System.out.println(boolean_variable ? "print true": "print false");这个有两个点的语法是什么：在哪里可以找到有关它的信息？它只适用于布尔值还是以其他不同的方式实现？

问Java: println中的布尔值(布尔值？"print true":"print false")
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问Java: println中的布尔值(布尔值？"print true":"print false")
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