How to Use is_bool with filter_input to Handle Boolean Values in PHP

gitbox 2025-09-02

<span><span><span class="hljs-meta"><?php</span></span><span>
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</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"The article is about to start…"</span></span><span>;
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<p><hr></p>
<p><h1>How to Use <code>is_bool

Here, FILTER_VALIDATE_BOOLEAN will parse the input value into a boolean. If the user submits “true”, “1”, “on” or “yes”, it will return true; otherwise, it returns false.

2. Using is_bool to Validate Data Type

Although filter_input can convert input to a boolean, sometimes we also want to ensure the variable’s type is indeed boolean. is_bool helps us perform this check:

</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">is_bool</span></span><span>(</span><span><span class="hljs-variable">$subscribe</span></span><span>)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"The input is a boolean: "</span></span><span> . (</span><span><span class="hljs-variable">$subscribe</span></span><span> ? </span><span><span class="hljs-string">&#039;true&#039;</span></span><span> : </span><span><span class="hljs-string">&#039;false&#039;</span></span><span>);
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"The input is not a boolean"</span></span><span>;
}

Combining filter_input with is_bool allows for both safe and precise boolean handling.

3. Complete Example

&lt;?php
</span><span><span class="hljs-variable">$subscribe</span></span><span> = </span><span><span class="hljs-title function_ invoke__">filter_input</span></span><span>(INPUT_POST, </span><span><span class="hljs-string">&#039;subscribe&#039;</span></span><span>, FILTER_VALIDATE_BOOLEAN);

</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">is_bool</span></span><span>(</span><span><span class="hljs-variable">$subscribe</span></span><span>)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"User subscription status: "</span></span><span> . (</span><span><span class="hljs-variable">$subscribe</span></span><span> ? </span><span><span class="hljs-string">&#039;Subscribed&#039;</span></span><span> : </span><span><span class="hljs-string">&#039;Not Subscribed&#039;</span></span><span>);
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Failed to get a valid boolean value"</span></span><span>;
}
?&gt;

This method allows you to safely retrieve boolean values from user input and use them directly in your logic without worrying about type errors.

4. Summary

Using filter_input with FILTER_VALIDATE_BOOLEAN safely retrieves boolean values from external input.
Using is_bool validates the data type, preventing non-boolean values from entering your logic by mistake.
This combination is especially useful for form submissions, API parameter handling, and similar scenarios.

With these methods, PHP developers can handle boolean user input more easily while ensuring code robustness and security.