blocks|key|1917040|text|把它写下来？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1917041|if(pstmt+!=+null)+pstmt.close();|code-block|syntax|javascript|1917042|完全一样长。|1917043|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Just write it out?

<pre><code>if(pstmt != null) pstmt.close();
</code></pre>

It's the exact same length.

blocks|key|1917061|text|相反，不，你不能那样做。尝试如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1917062|if(bool1+&&+bool2)+voidFunc1();|code-block|syntax|javascript|1917063|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25^0|3|9|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.25" rel="noreferrer">No, you cannot do that.</a>
Instead try this:

<pre><code>if(bool1 &amp;&amp; bool2) voidFunc1();
</code></pre>

blocks|key|536213|text|为什么在只有一种选择的情况下使用三值运算符？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|536214|if+(pstmt+!=+null)+pstmt.close();+|code-block|syntax|javascript|536215|够了！|536216|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Why using ternary operator when you have only one choice?

<pre><code>if (pstmt != null) pstmt.close(); 
</code></pre>

is enough!

blocks|key|1917108|text|三元if算子是一种特殊的三值算子。一种类型的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1917109|来自Wiki：|1917110|在数学中，三元运算是n=+3的n元运算.|blockquote|1917111|这意味着你需要所有三个操作数。|1917112|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Ternary_operation^0|2|2|0|2|5|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|H|3|I|5|J|7|11|8|@]|D|@]|E|$]]|$1|K|3|L|5|6|7|12|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

Ternary <code>if</code> operator is the particular ternary operator. One of a kind.

From <a href="http://en.wikipedia.org/wiki/Ternary_operation">Wiki:</a>

<blockquote>
 In mathematics, a ternary operation is an n-ary operation with n = 3.
</blockquote>

It means all 3 operands are required for you.

blocks|key|2997145|text|三值运算被称为三元运算，因为它有3个参数，如果它需要2，则是一个二进制运算。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2997146|如上所述，它是一个返回值的表达式。|offset|length|style|BOLD|2997147|如果省略了“否则”，则会出现一个未定义的情况，即表达式将不返回值。|2997148|因此，正如在其他答案中所指出的，您应该使用if+语句。|2997149|entityMap^0|0|D|3|0|0|O|2|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@$D|P|E|Q|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|S|8|@$D|T|E|U|F|G]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|M|$]]

A ternary operation is called ternary beacause it takes 3 arguments, if it takes 2 it is a binary operation.

And as noted above, it is an expression returning a value.

If you omit the else you would have an undefined situation where the expression would not return a value.

So as also noted in other answer, you should use an if statement.

blocks|key|1917144|text|正如其他答案中提到的，您不能使用三元操作符来执行此操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1917145|但是，如果需要，您可以使用Java+8+可选和lambda将这种逻辑放入一个语句中：|offset|length|1917146|Optional.of(pstmt).ifPresent((p)+->+p.close())|code-block|syntax|javascript|1917147|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html^0|0|K|2|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@$D|U|E|V|1|W]]|A|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

As mentioned in the other answers, you can't use a ternary operator to do this. 

However, if the need strikes you, you can use Java 8 <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html" rel="noreferrer">Optional</a> and lambdas to put this kind of logic into a single statement:

<pre><code>Optional.of(pstmt).ifPresent((p) -&gt; p.close())
</code></pre>

blocks|key|2997204|text|您不能在不使用其他类的情况下使用三元的，但是要在一行中执行“if-+use”，可以使用Java+8+Optional类。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2997205|PreparedStatement+pstmt;

//....+

Optional.ofNullable(pstmt).ifPresent(pstmt::close);+//+<-+but+IOException+will+still+happen+here.+Handle+it.|code-block|syntax|javascript|2997206|entityMap^0|1E|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You cannot use ternary without else, but to do a "if-without-else" in one line, you can use Java 8 <code>Optional</code> class.

<pre><code>PreparedStatement pstmt;

//.... 

Optional.ofNullable(pstmt).ifPresent(pstmt::close); // &lt;- but IOException will still happen here. Handle it.
</code></pre>

blocks|key|1917183|text|在JavaScript中，您可以简单地这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1917184|expression+?+doAction()+:+undefined|code-block|syntax|javascript|1917185|因为这就是真正的if语句中实际发生的事情，所以the子句就是没有定义的。我想你可以做同样的事情(几乎？)任何编程语言，只要放置一个不返回值的空类型变量，它就不会导致任何编译错误。|1917186|或者，如果其他所有操作都失败了，只需创建一个返回函数即可。|1917187|function+oy(x1,x2){if(x1)+return+x2();}

oy(etzem==6,+()=>yichoyliss=8);|1917188|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Well in JavaScript you can simply do:
<pre><code>expression ? doAction() : undefined
</code></pre>
since that's what's literally actually happening in a real if statement, the else clause is simply undefined. I image you can do pretty much the same thing in (almost?) any programming language, for the else clause just put a null-type variable that doesn't return a value, it shouldn't cause any compile errors.
or just make a function to return if all else fails
<pre><code>function oy(x1,x2){if(x1) return x2();}

oy(etzem==6, ()=&gt;yichoyliss=8);

</code></pre>

blocks|key|536297|text|是的，能实际上是这样做的(至少在JavaScript中)：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|536298|condition+&&+x+=+true;|code-block|syntax|javascript|536299|或者(在JavaScript中，在Java中可能有类似的方法)：|536300|void(condition+&&+x+=+true)|536301|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2932754/ternary-operators-in-javascript-without-an-else^0|3|1|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

Yes you <a href="https://stackoverflow.com/questions/2932754/ternary-operators-in-javascript-without-an-else">can</a> do that actually (in JavaScript at least):

<pre><code>condition &amp;&amp; x = true;
</code></pre>

or (in JavaScript, and there might be a similar way to do this in Java):

<pre><code>void(condition &amp;&amp; x = true)
</code></pre>

blocks|key|536307|text|pstmt+!=+null+&&+pstmt.close;|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|536308|上面的代码行转换为表达式的左侧“转换”为真正的->时执行右侧。|536309|entityMap^0|0|T|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|N|8|@]|D|@]|E|$]]]|I|$]]

<code>pstmt != null &amp;&amp; pstmt.close;</code>
The line of code above translates to When the left side of the expression &quot;translates&quot; to true -&gt; execute the right side.

blocks|key|2997273|text|用途：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2997274|<logic+Expression>+?+<method>+:+null;|code-block|syntax|javascript|2997275|示例：|2997276|(pstmt!=null)+?+pstmt.close+:+null;|2997277|是肮脏的解决方案但有效..。|2997278|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

use:
<pre><code>&lt;logic Expression&gt; ? &lt;method&gt; : null;
</code></pre>
Example:
<pre><code>(pstmt!=null) ? pstmt.close : null;
</code></pre>
is dirty solution but works...

So far from I have been searching through the net, the statement always have if and else condition such as <code>a ? b : c</code>. I would like to know whether the <code>if</code> ternary statement can be used without <code>else</code>. 
Assuming i have the following code, i wish to close the <code>PreparedStatement</code> if it is not null

(I am using Java programming language.)

<pre><code>PreparedStatement pstmt;

//.... 

(pstmt!=null) ? pstmt.close : &lt;do nothing&gt;;
</code></pre>

If without else ternary operator

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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到目前为止，我一直在网络中搜索，语句始终具有if和a ? b : c这样的条件。我想知道是否可以不使用if三元语句而不使用else。假设我有下面的代码，如果PreparedStatement不是null，我希望关闭它(我正在使用Java编程语言。)PreparedStatement pstmt;//.... (pstm...

问如果没有其他三元算子
EN

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问如果没有其他三元算子EN