blocks|key|1429201|text|是,|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1429202|if(x)+{

}|code-block|syntax|javascript|1429203|是简洁的等价物|1429204|if(x+==+true)+{

}|1429205|正如@Sotirios所指出的，它们在字节码级别上是不同的。考虑以下Java类：|1429206|class+Test+{+
+++public+void+foo()+{+
++++++boolean+x+=+true;
++++++if(x+==+true)+{+
++++++}
+++}
}|1429207|排放：|1429208|++public+void+foo();
++++Code:
+++++++0:+iconst_1++++++
+++++++1:+istore_1++++++
+++++++2:+iload_1+++++++
+++++++3:+iconst_1++++++
+++++++4:+if_icmpne+++++7
+++++++7:+return+|1429209|vs|1429210|class+Test+{+
+++public+void+foo()+{+
++++++boolean+x+=+true;
++++++if(x)+{+
++++++}
+++}
}|1429211|它释放出：|1429212|++public+void+foo();
++++Code:
+++++++0:+iconst_1++++++
+++++++1:+istore_1++++++
+++++++2:+iload_1+++++++
+++++++3:+ifeq++++++++++6
+++++++6:+return++|1429213|我不认为这与程序的性能或正确性有任何关系。|1429214|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|16|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|18|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|D|7|1F|8|@]|9|@]|A|$E|F]]|$1|10|3|11|5|6|7|1G|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]]|13|$]]

Yes,

<pre><code>if(x) {

}
</code></pre>

is the succinct equivalent of

<pre><code>if(x == true) {

}
</code></pre>

As @Sotirios points out, they are different at the bytecode level. Consider the following Java class:

<pre><code>class Test { 
 public void foo() { 
 boolean x = true;
 if(x == true) { 
 }
 }
}
</code></pre>

emits:

<pre><code> public void foo();
 Code:
 0: iconst_1 
 1: istore_1 
 2: iload_1 
 3: iconst_1 
 4: if_icmpne 7
 7: return 
</code></pre>

vs

<pre><code>class Test { 
 public void foo() { 
 boolean x = true;
 if(x) { 
 }
 }
}
</code></pre>

which emits:

<pre><code> public void foo();
 Code:
 0: iconst_1 
 1: istore_1 
 2: iload_1 
 3: ifeq 6
 6: return 
</code></pre>

I don't think this has any bearing on the performance or correctness of the program.

blocks|key|2146705|text|是的，是这样的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2146706|if检查条件是否为真，如果为真，则执行body语句。所以x需要是一个boolean表达式。|offset|length|style|CODE|2146707|事实上，如果x是一个布尔表达式，那么x就相当于x+==+true，所以您应该使用x，因为它更简洁。如果变量有一个布尔值的正确名称，这就变得更清楚了。|2146708|if+(this.isVisible())+{
++++this.hide();
}|code-block|syntax|javascript|2146709|与|2146710|if+(this.isVisible()+==+true)+{
++++this.hide();
}|2146711|第一本最好读一读。|2146712|entityMap^0|0|0|2|S|1|Y|7|0|6|1|I|1|N|9|14|1|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@$D|Y|E|Z|F|G]|$D|10|E|11|F|G]|$D|12|E|13|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|14|8|@$D|15|E|16|F|G]|$D|17|E|18|F|G]|$D|19|E|1A|F|G]|$D|1B|E|1C|F|G]]|9|@]|A|$]]|$1|J|3|K|5|L|7|1D|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Q|3|R|5|L|7|1F|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|1G|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]]|V|$]]

Yes, it is.

<code>if</code> checks if the condition is true, and if it is, executes the body statement. So <code>x</code> needs to be a <code>boolean</code> expression.

In fact <code>x</code> is equivalent to <code>x == true</code> if <code>x</code> is a boolean expression, so you should use <code>x</code> as it is more concise. This becomes clearer if the variable has a proper name for a boolean, e.g.

<pre><code>if (this.isVisible()) {
 this.hide();
}
</code></pre>

vs.

<pre><code>if (this.isVisible() == true) {
 this.hide();
}
</code></pre>

The first one is better to read.

blocks|key|1429175|text|是的，它的意思与您拥有if(x+==+true)的含义相同。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1429176|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Yes, it means the same thing as if you had if(x == true).

blocks|key|2146767|text|如果可以将x解析为布尔值，且值为"true"，则将执行“其他内容”。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2146768|entityMap^0|5|1|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

If <code>x</code> can be resolved as a boolean, and the value is "true", the "other stuff" will be executed.

blocks|key|2424873|text|是的，它和if(x+==+true)一样。实际上，建议使用if(x)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2424874|请参阅如果-然后和如果-然后-否则语句。教程中的示例。|2424875|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/tutorial/java/nutsandbolts/if.html^0|5|D|T|5|0|3|H|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@$9|V|A|W|1|X]]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Yes, it is same as <code>if(x == true)</code>. In fact <code>if(x)</code> is recommended.

See the examples in <a href="http://docs.oracle.com/javase/tutorial/java/nutsandbolts/if.html" rel="nofollow">The if-then and if-then-else Statements</a> in The Java tutorial.

blocks|key|2146839|text|两者的返回都是布尔值，在本例中两者都返回true。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2146840|例如：|2146841|x=是真的。|2146842|评价：|2146843|(+a)如(X)|2146844|(+b)如果(x==true)|2146845|两者都返回true，第一个原因是直接的值，第二个是因为表达式是true+(true==true)。|2146846|希望这也能帮到你。|2146847|values.html|offset|length|2146848|entityMap|0|LINK|mutability|MUTABLE|url|http://www.homeandlearn.co.uk/java/boolean_values.html^0|0|0|0|0|0|0|0|0|0|B|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|12|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|13|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|14|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|15|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|16|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|17|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|18|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|19|8|@]|9|@$R|1A|S|1B|1|1C]]|A|$]]|$1|T|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|U|$V|$5|W|X|Y|A|$Z|10]]]]

The return of both is a boolean, in this case both return true

For example:

x= true.

Evaluating:

a) if(x)

b) if(x==true)

Both return true, the first because is the value directly and the second because the expression it is true (true==true).

Hope this can help you too...

<a href="http://www.homeandlearn.co.uk/java/boolean_values.html" rel="nofollow">http://www.homeandlearn.co.uk/java/boolean_values.html</a>

blocks|key|2424951|text|杰普这是对的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2424952|也有一个简短的表格，你可能会感兴趣：|2424953|这意味着如果x为true，则返回true，否则返回false。|2424954|(x)+?+return+true+:+return+false;|code-block|syntax|javascript|2424955|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Jep this is right.

There is also a short form that could be interesting for you:

It means if x is true then return true, else return false.

<pre><code>(x) ? return true : return false;
</code></pre>

blocks|key|1429367|text|简短回答:是的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1429368|if语句以布尔表达式作为其条件。它可以是返回布尔值(如==+)的运算符的结果，也可以是布尔变量。基本上，布尔表达式是可以分配给布尔变量的任何东西：|offset|length|style|CODE|1429369|boolean+b+=+?;|code-block|syntax|javascript|1429370|因此，x+==+true有点多余，因为x本身已经足够了:这两个布尔表达式是等价的。不过，对于新程序员来说，编写==+true是很常见的，因为它更自然地“读”：如果x是真的，那么就写.|1429371|然而，您实际上应该读到，如果(x+==+true)是真的，那么请.因为这才是真正发生的事。在这里，您可以看到冗余是从哪里来的。更有经验的程序员知道这一点，他们更喜欢编写x和!x，而不是x+==+true和x+==+false。编译器并不重要，但对于程序员/维护人员来说，当他必须阅读时，这一点很重要：|1429372|if+(+((x+==+true)+&&+(y+==+true))+%7C%7C+(z+==+false)+)+{+...+}|1429373|相对于：|1429374|if+(+(x+&&+y)+%7C%7C+!z+)+{+...+}|1429375|entityMap^0|0|0|2|R|2|0|0|3|9|J|1|1J|7|29|1|0|E|B|2C|1|2E|2|2K|9|2U|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@$D|10|E|11|F|G]|$D|12|E|13|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|15|8|@$D|16|E|17|F|G]|$D|18|E|19|F|G]|$D|1A|E|1B|F|G]|$D|1C|E|1D|F|G]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1E|8|@$D|1F|E|1G|F|G]|$D|1H|E|1I|F|G]|$D|1J|E|1K|F|G]|$D|1L|E|1M|F|G]|$D|1N|E|1O|F|G]]|9|@]|A|$]]|$1|Q|3|R|5|J|7|1P|8|@]|9|@]|A|$K|L]]|$1|S|3|T|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|U|3|V|5|J|7|1R|8|@]|9|@]|A|$K|L]]|$1|W|3|-4|5|6|7|1S|8|@]|9|@]|A|$]]]|X|$]]

Short answer: yes.

An <code>if</code> statement takes a boolean expression as its condition. That can be the result of an operator which returns a boolean value such as <code>==</code>, or that can be a boolean variable. Basically, a boolean expression is anything which you can assign to a boolean variable:

<pre><code>boolean b = ?;
</code></pre>

Therefore, <code>x == true</code> is somewhat redundant, as <code>x</code> on its own already suffices: those two boolean expressions are equivalent. It's quite common for new programmers though to write the <code>== true</code>, as it "reads" more naturally: if <code>x</code> is true, then do...

However, you should actually read that as if <code>(x == true)</code> is true, then do... as that's what's actually happening. Here, you see where the redundancy comes from. More experienced programmers know this and prefer writing <code>x</code> and <code>!x</code> as opposed to <code>x == true</code> and <code>x == false</code> respectively. It doesn't matter for the compiler, but it matters for the programmer/maintainer when he has to read:

<pre><code>if ( ((x == true) &amp;&amp; (y == true)) || (z == false) ) { ... }
</code></pre>

as opposed to:

<pre><code>if ( (x &amp;&amp; y) || !z ) { ... }
</code></pre>

blocks|key|2146900|text|这是否意味着与if(x+==+true)相同？|type|blockquote|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2146901|是的，if(x+==+true)将给出与if+(x)相同的结果。它基于简单的逻辑：|unstyled|2146902|如果x是true条件，则x+==+true与true+==+true相同，后者被计算为与x的原始值相同的true。|unordered-list-item|2146903|如果x是false条件，则x+==+true与false+==+true相同，后者被计算为false，后者与x的原始值相同。|2146904|因此，无论x表达式的值如何，if+(x==true)都等同于if+(x)。|2146905|entityMap^0|7|D|0|3|D|K|6|0|2|1|4|4|C|9|M|C|18|1|1G|4|0|2|1|4|5|D|9|N|D|19|5|1I|1|0|5|1|E|C|U|6|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|I|3|J|5|K|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]|$9|14|A|15|B|C]|$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|L|3|M|5|K|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]|$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]]|D|@]|E|$]]|$1|N|3|O|5|H|7|1P|8|@$9|1Q|A|1R|B|C]|$9|1S|A|1T|B|C]|$9|1U|A|1V|B|C]]|D|@]|E|$]]|$1|P|3|-4|5|H|7|1W|8|@]|D|@]|E|$]]]|Q|$]]

<blockquote>
 Does this mean the same thing as <code>if(x == true)</code>?
</blockquote>

Yes <code>if(x == true)</code> will give same results as <code>if (x)</code>. It is based on simple logic: 

<ul>
<li>if <code>x</code> is <code>true</code> condition <code>x == true</code> is same as <code>true == true</code> which is evaluated to <code>true</code> which is same as original value of <code>x</code></li>
<li>if <code>x</code> is <code>false</code> condition <code>x == true</code> is same as <code>false == true</code> which is evaluated to <code>false</code> which again is same as original value of <code>x</code></li>
</ul>

So regardless of value of <code>x</code> expression <code>if (x==true)</code> is equivalent to <code>if (x)</code>.

blocks|key|2425011|text|是的，两者都是&+True。给你同样的结果。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2425012|if(x)+is+more+appropriate|code-block|syntax|javascript|2425013|在编程语言中，任何数字(而不是+)都被认为是True。|2425014|假设我取一个数字，是5|2425015|if(x)+or+if(5)|2425016|因为5不等于，或者您可以说5!=0，所以它是True。|2425017|entityMap^0|9|4|0|0|M|4|0|A|1|0|0|2|1|D|4|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|O|3|P|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|Q|3|R|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]]|T|$]]

Yes, both are Same &amp; True. And give you the same result.
<pre><code>if(x) is more appropriate
</code></pre>
Reason, In Programming language, any number but not 0 is considered as True.
Suppose I take a number which is 5:
<pre><code>if(x) or if(5)
</code></pre>
because 5 is not equal to 0 or you can say 5!=0 that why it's True.

Ok, so let's say I have an if statement and a boolean x:

<pre><code>if (x) {
 // some stuff
}
</code></pre>

What happens here? Does this mean the same thing as <code>if(x == true)</code> ?

Is if(x) same as if(x==true)?

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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好的，假设我有一个if语句和一个布尔值x：if (x) {    // some stuff}这里发生了什么？这是否意味着与if(x == true)相同？

问if(x)是否与if(x==true)相同？
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