php小编小新为您揭示php中的真假。php作为一种流行的编程语言，常常被人误解或传播虚假信息。本文将从各种角度探讨php中的真实情况，帮助读者更好地了解这门语言的优缺点，避免被谣言误导。让我们一起来揭开php的真相！

使用 false 时，它不显示任何输出。值得注意的是，浏览器总是以字符串的形式呈现这些值。

在 php 中使用 true 和 false 作为布尔逻辑值

布尔值是逻辑值。它们可以是真或假。

两者在 php 中都是区分大小写的，也是 php 中的简单数据类型。

<code class="language-php hljs" data-lang="php"><span style="display:flex;"><span> <span style="color:#19177c">$true</span> <span style="color:#666">=</span> <span style="color:#008000;font-weight:bold">True</span>; <span style="color:#408080;font-style:italic">//returns 1 
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span> <span style="color:#19177c">$false</span> <span style="color:#666">=</span> <span style="color:#008000;font-weight:bold">False</span>; <span style="color:#408080;font-style:italic">// return nothing 
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#19177c">$true</span><span style="color:#666">.</span>PHP_EOL;
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#19177c">$false</span>;
</span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic">//using comparis<strong class="keylink">io</strong>n operator to check boolean values
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">if</span> (<span style="color:#19177c">$a</span> <span style="color:#666">==</span> <span style="color:#ba2121">"abc"</span>) {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"return boolean value"</span>; <span style="color:#408080;font-style:italic">//returns nothing since $a is not equal to abc thus it is a false
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span> }
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">if</span> (<span style="color:#008000;font-weight:bold">TRUE</span>) {
</span></span><span style="display:flex;"><span>	<span style="color:#408080;font-style:italic">//because true means true
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"Your condition is executed!"</span><span style="color:#666">.</span>PHP_EOL; 
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">if</span> (<span style="color:#008000;font-weight:bold">false</span>) {
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"It will print nothing"</span>; <span style="color:#408080;font-style:italic">//false returns nothing
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span> }
</span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic">//Determine integer comparisions with boolean values
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#666">5</span><span style="color:#666"><span style="color:#666">10</span>; <span style="color:#408080;font-style:italic">//returns 1 since 5 is actually less ten (condition true)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#666">10</span> <span style="color:#666">!=</span> <span style="color:#666">5</span>; <span style="color:#408080;font-style:italic">//returns 1 (true)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#666">5</span> <span style="color:#666">==</span> <span style="color:#666">4</span>; <span style="color:#408080;font-style:italic">//false
</span></span></span></span>

输出：

<code class="language-text hljs" data-lang="text"><span style="display:flex;"><span>1 
</span></span><span style="display:flex;"><span>Your condition is executed!
</span></span><span style="display:flex;"><span>11
</span></span>

在 PHP 中使用 var_dump() 函数确定布尔值

我们还可以在 php.ini 中转换布尔值。让我们首先了解这些参数的一些预定义值分配。

如果我们将以下值转换为布尔值，它们将被视为假：

• false 是 false。
• 0 也是 false。
• 诸如 0.0 和 -0.0 之类的浮点数也是 false。
• 具有 0 元素的数组是 false。
• NULL 是 false。

相反，所有其他值都被认为是 true。

我们可以借助转储布尔值信息的 var_dump() 函数来确定布尔值。

让我们用 var_dump 检查上面提到的错误类型：

<code class="language-php hljs" data-lang="php"><span style="display:flex;"><span><span style="color:#666"></span>php
</span></span><span style="display:flex;"><span>var_dump((bool) <span style="color:#008000;font-weight:bold">false</span>);<span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#ba2121">"0"</span>); <span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#666">0.0</span>);<span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#666">-</span><span style="color:#666">0.0</span>);<span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#008000;font-weight:bold">NULL</span>); <span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#008000;font-weight:bold">array</span>()); <span style="color:#408080;font-style:italic">//(false)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic">//true bools (a few examples)
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool)<span style="color:#008000;font-weight:bold">true</span>);<span style="color:#408080;font-style:italic">//true
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool)<span style="color:#666">1</span>);<span style="color:#408080;font-style:italic">//true
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool)<span style="color:#666">100</span>); <span style="color:#408080;font-style:italic">//true
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span>var_dump((bool) <span style="color:#008000;font-weight:bold">array</span>(<span style="color:#666">65</span>)); <span style="color:#408080;font-style:italic">//true
</span></span></span><span style="display:flex;"><span><span style="color:#408080;font-style:italic"></span><span style="color:#bc7a00">?&gt;</span><span >
</span></span></span>

输出：

<code class="language-text hljs" data-lang="text"><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(true)
</span></span><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(false)
</span></span><span style="display:flex;"><span>bool(true)
</span></span><span style="display:flex;"><span>bool(true)
</span></span><span style="display:flex;"><span>bool(true)
</span></span><span style="display:flex;"><span>bool(true)
</span></span>