Betul dan Salah dalam PHP

Editor PHP Xiaoxin mendedahkan kepada anda kebenaran dan kepalsuan dalam PHP. Sebagai bahasa pengaturcaraan yang popular, PHP sering disalahfahamkan atau penyebaran maklumat yang salah. Artikel ini akan meneroka situasi sebenar dalam PHP dari pelbagai sudut untuk membantu pembaca lebih memahami kebaikan dan keburukan bahasa ini dan mengelak daripada ditipu oleh khabar angin. Marilah kita mendedahkan kebenaran tentang PHP bersama-sama!

Apabila menggunakan false, ia tidak menunjukkan sebarang output. Perlu diingat bahawa pelayar sentiasa memaparkan nilai ini sebagai rentetan. 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><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><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></code></code>

输出：

<code><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></code></code>

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

Gunakan true< dalam <strong class="keylink">php</strong> / code> dan <code>false sebagai nilai logik Boolean

• Kedua-duanya sensitif huruf besar dalam php dan merupakan jenis data ringkas dalam php. false 是 false

  <code><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">?></span><span >
  </span></span></span></code></code>

  Salin selepas log masuk
  Output:

• <code><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></code></code>

  Salin selepas log masuk

  ---

  Gunakan fungsi var_dump() dalam PHP untuk menentukan nilai boolean0 也是 falseKami juga boleh menukar nilai boolean dalam php.ini. Mari kita fahami beberapa penetapan nilai pratakrif dahulu untuk parameter ini.

• Jika kita menukar nilai berikut kepada boolean, nilai tersebut akan dianggap sebagai false: 0.0 和 -0.0 之类的浮点数也是 false
• 0 元素的数组是 false.
• NULL 是 false.
Seperti

. 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

mempunyai

.

🎜🎜. 🎜 🎜🎜Sebaliknya, semua nilai lain dianggap benar. 🎜🎜Kita boleh menentukan nilai Boolean dengan bantuan fungsi var_dump() yang membuang maklumat nilai Boolean. 🎜🎜Mari kami gunakan var_dump untuk menyemak jenis ralat yang disebutkan di atas: 🎜rrreee 🎜Output: 🎜rrreee

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